diff --git a/eth2/utils/ssz/src/tree_hash.rs b/eth2/utils/ssz/src/tree_hash.rs
index 5f62c1c7b8..9d6e75ea9c 100644
--- a/eth2/utils/ssz/src/tree_hash.rs
+++ b/eth2/utils/ssz/src/tree_hash.rs
@@ -30,6 +30,7 @@ pub fn merkle_hash(list: &mut Vec<Vec<u8>>) -> Vec<u8> {
                 // Hash two chuncks together
                 new_chunkz.append(&mut hash(two_chunks));
             }
+            chunk_size = HASHSIZE;
         }
         chunkz = new_chunkz;
     }