diff --git a/beacon_node/network/src/sync/simple_sync.rs b/beacon_node/network/src/sync/simple_sync.rs
index 0f7de6ab9..d3d0e1475 100644
--- a/beacon_node/network/src/sync/simple_sync.rs
+++ b/beacon_node/network/src/sync/simple_sync.rs
@@ -36,7 +36,7 @@ pub struct SimpleSync {
     /// The current state of the syncing protocol.
     state: SyncState,
     /// The network id, for quick HELLO RPC message lookup.
-    network_id: u8,
+    chain_id: u8,
     /// The latest epoch of the syncing chain.
     latest_finalized_epoch: Epoch,
     /// The latest block of the syncing chain.
@@ -53,7 +53,7 @@ impl SimpleSync {
             chain: beacon_chain.clone(),
             known_peers: HashMap::new(),
             state: SyncState::Idle,
-            network_id: beacon_chain.get_spec().network_id,
+            chain_id: beacon_chain.get_spec().chain_id,
             latest_finalized_epoch: state.finalized_epoch,
             latest_slot: state.slot - 1, //TODO: Build latest block function into Beacon chain and correct this
             log: sync_logger,
@@ -65,7 +65,7 @@ impl SimpleSync {
         let state = &self.chain.get_state();
         //TODO: Paul to verify the logic of these fields.
         HelloMessage {
-            network_id: self.network_id,
+            network_id: self.chain_id,
             latest_finalized_root: state.finalized_root,
             latest_finalized_epoch: state.finalized_epoch,
             best_root: Hash256::zero(), //TODO: build correct value as a beacon chain function
@@ -75,7 +75,7 @@ impl SimpleSync {
 
     pub fn validate_peer(&mut self, peer_id: PeerId, hello_message: HelloMessage) -> bool {
         // network id must match
-        if hello_message.network_id != self.network_id {
+        if hello_message.network_id != self.chain_id {
             return false;
         }
         // compare latest epoch and finalized root to see if they exist in our chain
diff --git a/eth2/types/src/chain_spec.rs b/eth2/types/src/chain_spec.rs
index 65ea5c4d4..5fa28b6ac 100644
--- a/eth2/types/src/chain_spec.rs
+++ b/eth2/types/src/chain_spec.rs
@@ -118,7 +118,7 @@ pub struct ChainSpec {
      *
      */
     pub boot_nodes: Vec<Multiaddr>,
-    pub network_id: u8,
+    pub chain_id: u8,
 }
 
 impl ChainSpec {
@@ -255,7 +255,7 @@ impl ChainSpec {
              * Boot nodes
              */
             boot_nodes: vec![],
-            network_id: 1, // foundation network id
+            chain_id: 1, // foundation chain id
         }
     }
 
@@ -272,7 +272,7 @@ impl ChainSpec {
 
         Self {
             boot_nodes,
-            network_id: 2, // lighthouse testnet network id
+            chain_id: 2, // lighthouse testnet chain id
             ..ChainSpec::few_validators()
         }
     }