diff --git a/interop/interop_client.js b/interop/interop_client.js
index a59a66b2..46ddecfb 100644
--- a/interop/interop_client.js
+++ b/interop/interop_client.js
@@ -380,7 +380,6 @@ function unimplementedService(client, done) {
   client.unimplementedCall({}, function(err, resp) {
     assert(err);
     assert.strictEqual(err.code, grpc.status.UNIMPLEMENTED);
-    assert(!err.message);
     done();
   });
 }