diff --git a/rpc/types.go b/rpc/types.go
index 6aa7d239b9..57f13e0354 100644
--- a/rpc/types.go
+++ b/rpc/types.go
@@ -128,7 +128,7 @@ const (
 )
 
 // UnmarshalJSON parses the given JSON fragment into a BlockNumber. It supports:
-// - "latest", "earliest" or "pending" as string arguments
+// - "latest", "earliest", "pending" and "confirmed" as string arguments
 // - the block number
 // Returned errors:
 // - an invalid block number error when the given argument isn't a known strings
@@ -147,6 +147,7 @@ func (bn *BlockNumber) UnmarshalJSON(data []byte) error {
 		return nil
 	case "confirmed":
 		*bn = ConfirmedBlockNumber
+		return nil
 	}
 
 	blckNum, err := hexutil.DecodeUint64(input)