diff --git a/grpc.go b/grpc.go
index b067d82..9a1843b 100644
--- a/grpc.go
+++ b/grpc.go
@@ -33,7 +33,7 @@ type grpcClient struct {
 
 func init() {
 	encoding.RegisterCodec(wrapCodec{jsonCodec{}})
-	encoding.RegisterCodec(wrapCodec{jsonCodec{}})
+	encoding.RegisterCodec(wrapCodec{protoCodec{}})
 	encoding.RegisterCodec(wrapCodec{bytesCodec{}})
 }