diff --git a/rpc/src/v1/traits/parity.rs b/rpc/src/v1/traits/parity.rs
index 165cf63d6..83d8b1981 100644
--- a/rpc/src/v1/traits/parity.rs
+++ b/rpc/src/v1/traits/parity.rs
@@ -178,7 +178,7 @@ build_rpc_trait! {
 		fn mode(&self) -> Result<String>;
 
 		/// Returns the chain ID used for transaction signing at the
-		/// current best block. An empty string is returned if not
+		/// current best block. None is returned if not
 		/// available.
 		#[rpc(name = "parity_chainId")]
 		fn chain_id(&self) -> Result<Option<U64>>;