diff --git a/beacon_node/src/main.rs b/beacon_node/src/main.rs
index c3182c789b..eacbffa3ef 100644
--- a/beacon_node/src/main.rs
+++ b/beacon_node/src/main.rs
@@ -119,11 +119,7 @@ fn main() {
                             // Get domain from genesis fork_version
                             spec.genesis_epoch,
                             Domain::Deposit,
-                            &Fork {
-                                previous_version: spec.genesis_fork_version,
-                                current_version: spec.genesis_fork_version,
-                                epoch: spec.genesis_epoch,
-                            },
+                            &Fork::genesis(&spec),
                         ),
                     ),
                 },
diff --git a/eth2/types/src/chain_spec.rs b/eth2/types/src/chain_spec.rs
index 108516695d..ae521cc92a 100644
--- a/eth2/types/src/chain_spec.rs
+++ b/eth2/types/src/chain_spec.rs
@@ -1,4 +1,4 @@
-use crate::{Address, Epoch, Fork, Hash256, Slot};
+use crate::*;
 use bls::Signature;
 use int_to_bytes::int_to_bytes4;
 use serde_derive::Deserialize;
@@ -127,7 +127,7 @@ impl ChainSpec {
 
     /// Get the domain number that represents the fork meta and signature domain.
     ///
-    /// Spec v0.4.0
+    /// Spec v0.5.0
     pub fn get_domain(&self, epoch: Epoch, domain: Domain, fork: &Fork) -> u64 {
         let domain_constant = match domain {
             Domain::Deposit => self.domain_deposit,
@@ -138,9 +138,11 @@ impl ChainSpec {
             Domain::Transfer => self.domain_transfer,
         };
 
+        let mut bytes: Vec<u8> = fork.get_fork_version(epoch).to_vec();
+        bytes.append(&mut int_to_bytes4(domain_constant));
+
         let mut fork_and_domain = [0; 8];
-        fork_and_domain.copy_from_slice(&fork.get_fork_version(epoch));
-        fork_and_domain.copy_from_slice(&int_to_bytes4(domain_constant));
+        fork_and_domain.copy_from_slice(&bytes);
 
         u64::from_le_bytes(fork_and_domain)
     }
@@ -269,9 +271,34 @@ impl Default for ChainSpec {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use int_to_bytes::int_to_bytes8;
 
     #[test]
     fn test_foundation_spec_can_be_constructed() {
         let _ = ChainSpec::foundation();
     }
+
+    fn test_domain(domain_type: Domain, raw_domain: u32, spec: &ChainSpec) {
+        let fork = Fork::genesis(&spec);
+        let epoch = Epoch::new(0);
+
+        let domain = spec.get_domain(epoch, domain_type, &fork);
+
+        let mut expected = fork.get_fork_version(epoch).to_vec();
+        expected.append(&mut int_to_bytes4(raw_domain));
+
+        assert_eq!(int_to_bytes8(domain), expected);
+    }
+
+    #[test]
+    fn test_get_domain() {
+        let spec = ChainSpec::foundation();
+
+        test_domain(Domain::Deposit, spec.domain_deposit, &spec);
+        test_domain(Domain::Attestation, spec.domain_attestation, &spec);
+        test_domain(Domain::Proposal, spec.domain_proposal, &spec);
+        test_domain(Domain::Exit, spec.domain_exit, &spec);
+        test_domain(Domain::Randao, spec.domain_randao, &spec);
+        test_domain(Domain::Transfer, spec.domain_transfer, &spec);
+    }
 }
diff --git a/eth2/types/src/fork.rs b/eth2/types/src/fork.rs
index f0e3d10467..b780b95ef3 100644
--- a/eth2/types/src/fork.rs
+++ b/eth2/types/src/fork.rs
@@ -48,4 +48,49 @@ mod tests {
     use super::*;
 
     ssz_tests!(Fork);
+
+    fn test_genesis(version: u32, epoch: Epoch) {
+        let mut spec = ChainSpec::foundation();
+
+        spec.genesis_fork_version = version;
+        spec.genesis_epoch = epoch;
+
+        let fork = Fork::genesis(&spec);
+
+        assert_eq!(fork.epoch, spec.genesis_epoch, "epoch incorrect");
+        assert_eq!(
+            fork.previous_version, fork.current_version,
+            "previous and current are not identical"
+        );
+        assert_eq!(
+            fork.current_version,
+            version.to_le_bytes(),
+            "current version incorrect"
+        );
+    }
+
+    #[test]
+    fn genesis() {
+        test_genesis(0, Epoch::new(0));
+        test_genesis(9, Epoch::new(11));
+        test_genesis(2_u32.pow(31), Epoch::new(2_u64.pow(63)));
+        test_genesis(u32::max_value(), Epoch::max_value());
+    }
+
+    #[test]
+    fn get_fork_version() {
+        let previous_version = [1; 4];
+        let current_version = [2; 4];
+        let epoch = Epoch::new(10);
+
+        let fork = Fork {
+            previous_version,
+            current_version,
+            epoch,
+        };
+
+        assert_eq!(fork.get_fork_version(epoch - 1), previous_version);
+        assert_eq!(fork.get_fork_version(epoch), current_version);
+        assert_eq!(fork.get_fork_version(epoch + 1), current_version);
+    }
 }
diff --git a/validator_client/src/duties/epoch_duties.rs b/validator_client/src/duties/epoch_duties.rs
index 35668b4a9d..71f5f26ab5 100644
--- a/validator_client/src/duties/epoch_duties.rs
+++ b/validator_client/src/duties/epoch_duties.rs
@@ -81,8 +81,8 @@ impl DutiesReader for EpochDutiesMap {
         //
         // It will almost certainly cause signatures to fail verification.
         Ok(Fork {
-            previous_version: 0,
-            current_version: 0,
+            previous_version: [0; 4],
+            current_version: [0; 4],
             epoch: Epoch::new(0),
         })
     }