diff --git a/beacon_node/beacon_chain/src/beacon_chain.rs b/beacon_node/beacon_chain/src/beacon_chain.rs
index db5ea1cdb6..9a55851a49 100644
--- a/beacon_node/beacon_chain/src/beacon_chain.rs
+++ b/beacon_node/beacon_chain/src/beacon_chain.rs
@@ -332,8 +332,8 @@ where
         // If required, transition the new state to the present slot.
         for _ in state.slot.as_u64()..present_slot.as_u64() {
             // Ensure the next epoch state caches are built in case of an epoch transition.
-            state.build_epoch_cache(RelativeEpoch::NextWithoutRegistryChange, &self.spec)?;
-            state.build_epoch_cache(RelativeEpoch::NextWithRegistryChange, &self.spec)?;
+            state.build_committee_cache(RelativeEpoch::NextWithoutRegistryChange, &self.spec)?;
+            state.build_committee_cache(RelativeEpoch::NextWithRegistryChange, &self.spec)?;
 
             per_slot_processing(&mut *state, &self.spec)?;
         }
@@ -439,7 +439,7 @@ where
     pub fn block_proposer(&self, slot: Slot) -> Result<usize, BeaconStateError> {
         self.state
             .write()
-            .build_epoch_cache(RelativeEpoch::Current, &self.spec)?;
+            .build_committee_cache(RelativeEpoch::Current, &self.spec)?;
 
         let index = self.state.read().get_beacon_proposer_index(
             slot,
@@ -669,7 +669,7 @@ where
 
         let mut state = self.state.read().clone();
 
-        state.build_epoch_cache(RelativeEpoch::Current, &self.spec)?;
+        state.build_committee_cache(RelativeEpoch::Current, &self.spec)?;
 
         trace!("Finding attestations for new block...");
 
diff --git a/eth2/state_processing/benches/bench_block_processing.rs b/eth2/state_processing/benches/bench_block_processing.rs
index 80be1828ff..978d532f14 100644
--- a/eth2/state_processing/benches/bench_block_processing.rs
+++ b/eth2/state_processing/benches/bench_block_processing.rs
@@ -207,12 +207,12 @@ pub fn bench_block_processing(
     let spec = initial_spec.clone();
     c.bench(
         &format!("{}/block_processing", desc),
-        Benchmark::new("build_previous_state_epoch_cache", move |b| {
+        Benchmark::new("build_previous_state_committee_cache", move |b| {
             b.iter_batched(
                 || state.clone(),
                 |mut state| {
                     state
-                        .build_epoch_cache(RelativeEpoch::Previous, &spec)
+                        .build_committee_cache(RelativeEpoch::Previous, &spec)
                         .unwrap();
                     state
                 },
@@ -227,12 +227,12 @@ pub fn bench_block_processing(
     let spec = initial_spec.clone();
     c.bench(
         &format!("{}/block_processing", desc),
-        Benchmark::new("build_current_state_epoch_cache", move |b| {
+        Benchmark::new("build_current_state_committee_cache", move |b| {
             b.iter_batched(
                 || state.clone(),
                 |mut state| {
                     state
-                        .build_epoch_cache(RelativeEpoch::Current, &spec)
+                        .build_committee_cache(RelativeEpoch::Current, &spec)
                         .unwrap();
                     state
                 },
diff --git a/eth2/state_processing/src/get_genesis_state.rs b/eth2/state_processing/src/get_genesis_state.rs
index 6638b5246f..210d1a0a7b 100644
--- a/eth2/state_processing/src/get_genesis_state.rs
+++ b/eth2/state_processing/src/get_genesis_state.rs
@@ -30,7 +30,7 @@ pub fn get_genesis_state<T: EthSpec>(
     }
 
     // Ensure the current epoch cache is built.
-    state.build_epoch_cache(RelativeEpoch::Current, spec)?;
+    state.build_committee_cache(RelativeEpoch::Current, spec)?;
 
     // Set all the active index roots to be the genesis active index root.
     let active_validator_indices = state
diff --git a/eth2/state_processing/src/per_block_processing.rs b/eth2/state_processing/src/per_block_processing.rs
index 9f40bffd7a..db73c96187 100644
--- a/eth2/state_processing/src/per_block_processing.rs
+++ b/eth2/state_processing/src/per_block_processing.rs
@@ -79,8 +79,8 @@ fn per_block_processing_signature_optional<T: EthSpec>(
     process_block_header(state, block, spec)?;
 
     // Ensure the current and previous epoch cache is built.
-    state.build_epoch_cache(RelativeEpoch::Previous, spec)?;
-    state.build_epoch_cache(RelativeEpoch::Current, spec)?;
+    state.build_committee_cache(RelativeEpoch::Previous, spec)?;
+    state.build_committee_cache(RelativeEpoch::Current, spec)?;
 
     if should_verify_block_signature {
         verify_block_signature(&state, &block, &spec)?;
@@ -315,7 +315,7 @@ pub fn process_attestations<T: EthSpec>(
     );
 
     // Ensure the previous epoch cache exists.
-    state.build_epoch_cache(RelativeEpoch::Previous, spec)?;
+    state.build_committee_cache(RelativeEpoch::Previous, spec)?;
 
     // Verify attestations in parallel.
     attestations
diff --git a/eth2/state_processing/src/per_epoch_processing.rs b/eth2/state_processing/src/per_epoch_processing.rs
index f1ca42eda8..69ee565fb4 100644
--- a/eth2/state_processing/src/per_epoch_processing.rs
+++ b/eth2/state_processing/src/per_epoch_processing.rs
@@ -34,8 +34,8 @@ pub fn per_epoch_processing<T: EthSpec>(
     spec: &ChainSpec,
 ) -> Result<(), Error> {
     // Ensure the previous and next epoch caches are built.
-    state.build_epoch_cache(RelativeEpoch::Previous, spec)?;
-    state.build_epoch_cache(RelativeEpoch::Current, spec)?;
+    state.build_committee_cache(RelativeEpoch::Previous, spec)?;
+    state.build_committee_cache(RelativeEpoch::Current, spec)?;
 
     // Load the struct we use to assign validators into sets based on their participation.
     //
diff --git a/eth2/types/src/beacon_state.rs b/eth2/types/src/beacon_state.rs
index f709bc68fa..2671257f8e 100644
--- a/eth2/types/src/beacon_state.rs
+++ b/eth2/types/src/beacon_state.rs
@@ -1,4 +1,6 @@
-use self::epoch_cache::{get_active_validator_indices, EpochCache, Error as EpochCacheError};
+use self::committee_cache::{
+    get_active_validator_indices, CommitteeCache, Error as CommitteeCacheError,
+};
 use self::exit_cache::ExitCache;
 use crate::test_utils::TestRandom;
 use crate::*;
@@ -18,7 +20,7 @@ use tree_hash_derive::{CachedTreeHash, TreeHash};
 pub use beacon_state_types::*;
 
 mod beacon_state_types;
-mod epoch_cache;
+mod committee_cache;
 mod exit_cache;
 mod pubkey_cache;
 mod tests;
@@ -50,11 +52,11 @@ pub enum Error {
         cache_len: usize,
         registry_len: usize,
     },
-    PreviousEpochCacheUninitialized,
-    CurrentEpochCacheUninitialized,
+    PreviousCommitteeCacheUninitialized,
+    CurrentCommitteeCacheUninitialized,
     RelativeEpochError(RelativeEpochError),
-    EpochCacheUninitialized(RelativeEpoch),
-    EpochCacheError(EpochCacheError),
+    CommitteeCacheUninitialized(RelativeEpoch),
+    CommitteeCacheError(CommitteeCacheError),
     TreeHashCacheError(TreeHashCacheError),
 }
 
@@ -122,7 +124,7 @@ where
     #[ssz(skip_deserializing)]
     #[tree_hash(skip_hashing)]
     #[test_random(default)]
-    pub epoch_caches: [EpochCache; CACHED_EPOCHS],
+    pub committee_caches: [CommitteeCache; CACHED_EPOCHS],
     #[serde(default)]
     #[ssz(skip_serializing)]
     #[ssz(skip_deserializing)]
@@ -213,10 +215,10 @@ impl<T: EthSpec> BeaconState<T> {
             /*
              * Caching (not in spec)
              */
-            epoch_caches: [
-                EpochCache::default(),
-                EpochCache::default(),
-                EpochCache::default(),
+            committee_caches: [
+                CommitteeCache::default(),
+                CommitteeCache::default(),
+                CommitteeCache::default(),
             ],
             pubkey_cache: PubkeyCache::default(),
             tree_hash_cache: TreeHashCache::default(),
@@ -732,9 +734,9 @@ impl<T: EthSpec> BeaconState<T> {
 
     /// Build all the caches, if they need to be built.
     pub fn build_all_caches(&mut self, spec: &ChainSpec) -> Result<(), Error> {
-        self.build_epoch_cache(RelativeEpoch::Previous, spec)?;
-        self.build_epoch_cache(RelativeEpoch::Current, spec)?;
-        self.build_epoch_cache(RelativeEpoch::Next, spec)?;
+        self.build_committee_cache(RelativeEpoch::Previous, spec)?;
+        self.build_committee_cache(RelativeEpoch::Current, spec)?;
+        self.build_committee_cache(RelativeEpoch::Next, spec)?;
         self.update_pubkey_cache()?;
         self.update_tree_hash_cache()?;
         self.exit_cache
@@ -744,30 +746,30 @@ impl<T: EthSpec> BeaconState<T> {
     }
 
     /// Build an epoch cache, unless it is has already been built.
-    pub fn build_epoch_cache(
+    pub fn build_committee_cache(
         &mut self,
         relative_epoch: RelativeEpoch,
         spec: &ChainSpec,
     ) -> Result<(), Error> {
         let i = Self::cache_index(relative_epoch);
 
-        if self.epoch_caches[i].is_initialized_at(self.previous_epoch()) {
+        if self.committee_caches[i].is_initialized_at(self.previous_epoch()) {
             Ok(())
         } else {
-            self.force_build_epoch_cache(relative_epoch, spec)
+            self.force_build_committee_cache(relative_epoch, spec)
         }
     }
 
     /// Always builds the previous epoch cache, even if it is already initialized.
-    pub fn force_build_epoch_cache(
+    pub fn force_build_committee_cache(
         &mut self,
         relative_epoch: RelativeEpoch,
         spec: &ChainSpec,
     ) -> Result<(), Error> {
         let epoch = relative_epoch.into_epoch(self.current_epoch());
 
-        self.epoch_caches[Self::cache_index(relative_epoch)] =
-            EpochCache::initialized(&self, epoch, spec)?;
+        self.committee_caches[Self::cache_index(relative_epoch)] =
+            CommitteeCache::initialized(&self, epoch, spec)?;
         Ok(())
     }
 
@@ -779,9 +781,9 @@ impl<T: EthSpec> BeaconState<T> {
     pub fn advance_caches(&mut self) {
         let next = Self::cache_index(RelativeEpoch::Previous);
 
-        let caches = &mut self.epoch_caches[..];
+        let caches = &mut self.committee_caches[..];
         caches.rotate_left(1);
-        caches[next] = EpochCache::default();
+        caches[next] = CommitteeCache::default();
     }
 
     fn cache_index(relative_epoch: RelativeEpoch) -> usize {
@@ -794,22 +796,22 @@ impl<T: EthSpec> BeaconState<T> {
 
     /// Returns the cache for some `RelativeEpoch`. Returns an error if the cache has not been
     /// initialized.
-    fn cache(&self, relative_epoch: RelativeEpoch) -> Result<&EpochCache, Error> {
-        let cache = &self.epoch_caches[Self::cache_index(relative_epoch)];
+    fn cache(&self, relative_epoch: RelativeEpoch) -> Result<&CommitteeCache, Error> {
+        let cache = &self.committee_caches[Self::cache_index(relative_epoch)];
 
         if cache.is_initialized_at(relative_epoch.into_epoch(self.current_epoch())) {
             Ok(cache)
         } else {
-            Err(Error::EpochCacheUninitialized(relative_epoch))
+            Err(Error::CommitteeCacheUninitialized(relative_epoch))
         }
     }
 
     /// Drops the cache, leaving it in an uninitialized state.
     fn drop_cache(&mut self, relative_epoch: RelativeEpoch) {
-        self.epoch_caches[Self::cache_index(relative_epoch)] = EpochCache::default();
+        self.committee_caches[Self::cache_index(relative_epoch)] = CommitteeCache::default();
     }
 
-    // FIXME(sproul): drop_previous/current_epoch_cache
+    // FIXME(sproul): drop_previous/current_committee_cache
 
     /// Updates the pubkey cache, if required.
     ///
@@ -870,9 +872,9 @@ impl<T: EthSpec> BeaconState<T> {
     }
 }
 
-impl From<EpochCacheError> for Error {
-    fn from(e: EpochCacheError) -> Error {
-        Error::EpochCacheError(e)
+impl From<CommitteeCacheError> for Error {
+    fn from(e: CommitteeCacheError) -> Error {
+        Error::CommitteeCacheError(e)
     }
 }
 
diff --git a/eth2/types/src/beacon_state/epoch_cache.rs b/eth2/types/src/beacon_state/committee_cache.rs
similarity index 98%
rename from eth2/types/src/beacon_state/epoch_cache.rs
rename to eth2/types/src/beacon_state/committee_cache.rs
index 3c4cb6c054..10b2d2a996 100644
--- a/eth2/types/src/beacon_state/epoch_cache.rs
+++ b/eth2/types/src/beacon_state/committee_cache.rs
@@ -14,7 +14,7 @@ pub enum Error {
 mod tests;
 
 #[derive(Debug, Default, PartialEq, Clone, Serialize, Deserialize)]
-pub struct EpochCache {
+pub struct CommitteeCache {
     /// `Some(epoch)` if the cache is initialized, where `epoch` is the cache it holds.
     initialized_epoch: Option<Epoch>,
     shuffling_start_shard: u64,
@@ -26,13 +26,13 @@ pub struct EpochCache {
     pub attestation_duties: Vec<Option<AttestationDuty>>,
 }
 
-impl EpochCache {
+impl CommitteeCache {
     /// Return a new, fully initialized cache.
     pub fn initialized<T: EthSpec>(
         state: &BeaconState<T>,
         epoch: Epoch,
         spec: &ChainSpec,
-    ) -> Result<EpochCache, BeaconStateError> {
+    ) -> Result<CommitteeCache, BeaconStateError> {
         let relative_epoch = RelativeEpoch::from_epoch(state.current_epoch(), epoch)
             .map_err(|_| BeaconStateError::EpochOutOfBounds)?;
 
@@ -74,7 +74,7 @@ impl EpochCache {
         )
         .ok_or_else(|| Error::UnableToShuffle)?;
 
-        let mut cache = EpochCache {
+        let mut cache = CommitteeCache {
             initialized_epoch: Some(epoch),
             shuffling_start_shard,
             shuffling,
diff --git a/eth2/types/src/beacon_state/epoch_cache/tests.rs b/eth2/types/src/beacon_state/committee_cache/tests.rs
similarity index 84%
rename from eth2/types/src/beacon_state/epoch_cache/tests.rs
rename to eth2/types/src/beacon_state/committee_cache/tests.rs
index df8ed223b5..9ea863ada9 100644
--- a/eth2/types/src/beacon_state/epoch_cache/tests.rs
+++ b/eth2/types/src/beacon_state/committee_cache/tests.rs
@@ -23,7 +23,7 @@ fn fails_without_validators() {
     let spec = &FewValidatorsEthSpec::spec();
 
     assert_eq!(
-        EpochCache::initialized(&state, state.current_epoch(), &spec),
+        CommitteeCache::initialized(&state, state.current_epoch(), &spec),
         Err(BeaconStateError::InsufficientValidators)
     );
 }
@@ -33,16 +33,16 @@ fn initializes_with_the_right_epoch() {
     let state = new_state::<FewValidatorsEthSpec>(16, Slot::new(0));
     let spec = &FewValidatorsEthSpec::spec();
 
-    let cache = EpochCache::default();
+    let cache = CommitteeCache::default();
     assert_eq!(cache.initialized_epoch, None);
 
-    let cache = EpochCache::initialized(&state, state.current_epoch(), &spec).unwrap();
+    let cache = CommitteeCache::initialized(&state, state.current_epoch(), &spec).unwrap();
     assert_eq!(cache.initialized_epoch, Some(state.current_epoch()));
 
-    let cache = EpochCache::initialized(&state, state.previous_epoch(), &spec).unwrap();
+    let cache = CommitteeCache::initialized(&state, state.previous_epoch(), &spec).unwrap();
     assert_eq!(cache.initialized_epoch, Some(state.previous_epoch()));
 
-    let cache = EpochCache::initialized(&state, state.next_epoch(), &spec).unwrap();
+    let cache = CommitteeCache::initialized(&state, state.next_epoch(), &spec).unwrap();
     assert_eq!(cache.initialized_epoch, Some(state.next_epoch()));
 }
 
@@ -78,13 +78,13 @@ fn shuffles_for_the_right_epoch() {
         .unwrap()
     };
 
-    let cache = EpochCache::initialized(&state, state.current_epoch(), spec).unwrap();
+    let cache = CommitteeCache::initialized(&state, state.current_epoch(), spec).unwrap();
     assert_eq!(cache.shuffling, shuffling_with_seed(current_seed));
 
-    let cache = EpochCache::initialized(&state, state.previous_epoch(), spec).unwrap();
+    let cache = CommitteeCache::initialized(&state, state.previous_epoch(), spec).unwrap();
     assert_eq!(cache.shuffling, shuffling_with_seed(previous_seed));
 
-    let cache = EpochCache::initialized(&state, state.next_epoch(), spec).unwrap();
+    let cache = CommitteeCache::initialized(&state, state.next_epoch(), spec).unwrap();
     assert_eq!(cache.shuffling, shuffling_with_seed(next_seed));
 }
 
@@ -100,13 +100,13 @@ fn can_start_on_any_shard() {
     for i in 0..FewValidatorsEthSpec::shard_count() as u64 {
         state.latest_start_shard = i;
 
-        let cache = EpochCache::initialized(&state, state.current_epoch(), spec).unwrap();
+        let cache = CommitteeCache::initialized(&state, state.current_epoch(), spec).unwrap();
         assert_eq!(cache.shuffling_start_shard, i);
 
-        let cache = EpochCache::initialized(&state, state.previous_epoch(), spec).unwrap();
+        let cache = CommitteeCache::initialized(&state, state.previous_epoch(), spec).unwrap();
         assert_eq!(cache.shuffling_start_shard, i);
 
-        let cache = EpochCache::initialized(&state, state.next_epoch(), spec).unwrap();
+        let cache = CommitteeCache::initialized(&state, state.next_epoch(), spec).unwrap();
         assert_eq!(cache.shuffling_start_shard, i);
     }
 }
@@ -195,16 +195,16 @@ fn starts_on_the_correct_shard() {
     for i in 0..ExcessShardsEthSpec::shard_count() {
         state.latest_start_shard = i as u64;
 
-        let cache = EpochCache::initialized(&state, state.current_epoch(), spec).unwrap();
+        let cache = CommitteeCache::initialized(&state, state.current_epoch(), spec).unwrap();
         assert_eq!(cache.shuffling_start_shard as usize, i);
 
-        let cache = EpochCache::initialized(&state, state.previous_epoch(), spec).unwrap();
+        let cache = CommitteeCache::initialized(&state, state.previous_epoch(), spec).unwrap();
         assert_eq!(
             cache.shuffling_start_shard as usize,
             (i + shard_count - previous_shards) % shard_count
         );
 
-        let cache = EpochCache::initialized(&state, state.next_epoch(), spec).unwrap();
+        let cache = CommitteeCache::initialized(&state, state.next_epoch(), spec).unwrap();
         assert_eq!(
             cache.shuffling_start_shard as usize,
             (i + current_shards) % shard_count
diff --git a/eth2/types/src/beacon_state/tests.rs b/eth2/types/src/beacon_state/tests.rs
index 35f0269b1f..a70ecb52fd 100644
--- a/eth2/types/src/beacon_state/tests.rs
+++ b/eth2/types/src/beacon_state/tests.rs
@@ -89,11 +89,13 @@ fn test_cache_initialization<'a, T: EthSpec>(
     // Assuming the cache isn't already built, assert that a call to a cache-using function fails.
     assert_eq!(
         state.get_attestation_duties(0, relative_epoch),
-        Err(BeaconStateError::EpochCacheUninitialized(relative_epoch))
+        Err(BeaconStateError::CommitteeCacheUninitialized(
+            relative_epoch
+        ))
     );
 
     // Build the cache.
-    state.build_epoch_cache(relative_epoch, spec).unwrap();
+    state.build_committee_cache(relative_epoch, spec).unwrap();
 
     // Assert a call to a cache-using function passes.
     let _ = state
@@ -106,7 +108,9 @@ fn test_cache_initialization<'a, T: EthSpec>(
     // Assert a call to a cache-using function fail.
     assert_eq!(
         state.get_beacon_proposer_index(slot, relative_epoch, spec),
-        Err(BeaconStateError::EpochCacheUninitialized(relative_epoch))
+        Err(BeaconStateError::CommitteeCacheUninitialized(
+            relative_epoch
+        ))
     );
 }
 
@@ -256,12 +260,14 @@ mod committees {
         state.latest_randao_mixes = FixedLenVec::from(distinct_hashes);
 
         state
-            .build_epoch_cache(RelativeEpoch::Previous, spec)
+            .build_committee_cache(RelativeEpoch::Previous, spec)
             .unwrap();
         state
-            .build_epoch_cache(RelativeEpoch::Current, spec)
+            .build_committee_cache(RelativeEpoch::Current, spec)
+            .unwrap();
+        state
+            .build_committee_cache(RelativeEpoch::Next, spec)
             .unwrap();
-        state.build_epoch_cache(RelativeEpoch::Next, spec).unwrap();
 
         let cache_epoch = cache_epoch.into_epoch(state_epoch);
 
diff --git a/eth2/types/src/test_utils/builders/testing_beacon_state_builder.rs b/eth2/types/src/test_utils/builders/testing_beacon_state_builder.rs
index 90bddc4fd1..20ed8a893a 100644
--- a/eth2/types/src/test_utils/builders/testing_beacon_state_builder.rs
+++ b/eth2/types/src/test_utils/builders/testing_beacon_state_builder.rs
@@ -205,10 +205,10 @@ impl<T: EthSpec> TestingBeaconStateBuilder<T> {
         let state = &mut self.state;
 
         state
-            .build_epoch_cache(RelativeEpoch::Previous, spec)
+            .build_committee_cache(RelativeEpoch::Previous, spec)
             .unwrap();
         state
-            .build_epoch_cache(RelativeEpoch::Current, spec)
+            .build_committee_cache(RelativeEpoch::Current, spec)
             .unwrap();
 
         let current_epoch = state.current_epoch();