diff --git a/benchmark/benchmark.go b/benchmark/benchmark.go
index df1493bc6..7215d35a5 100644
--- a/benchmark/benchmark.go
+++ b/benchmark/benchmark.go
@@ -139,7 +139,7 @@ func DoStreamingRoundTrip(tc testpb.TestServiceClient, stream testpb.TestService
 
 // NewClientConn creates a gRPC client connection to addr.
 func NewClientConn(addr string) *grpc.ClientConn {
-	conn, err := grpc.Dial(addr)
+	conn, err := grpc.Dial(addr, grpc.WithInsecure())
 	if err != nil {
 		grpclog.Fatalf("NewClientConn(%q) failed to create a ClientConn %v", addr, err)
 	}
diff --git a/examples/route_guide/client/client.go b/examples/route_guide/client/client.go
index 51c6c1206..d281abba8 100644
--- a/examples/route_guide/client/client.go
+++ b/examples/route_guide/client/client.go
@@ -175,6 +175,8 @@ func main() {
 			creds = credentials.NewClientTLSFromCert(nil, sn)
 		}
 		opts = append(opts, grpc.WithTransportCredentials(creds))
+	} else {
+		opts = append(opts, grpc.WithInsecure())
 	}
 	conn, err := grpc.Dial(*serverAddr, opts...)
 	if err != nil {
diff --git a/interop/client/client.go b/interop/client/client.go
index 9c5ace504..c61337807 100644
--- a/interop/client/client.go
+++ b/interop/client/client.go
@@ -522,6 +522,8 @@ func main() {
 		} else if *testCase == "oauth2_auth_token" {
 			opts = append(opts, grpc.WithPerRPCCredentials(oauth.NewOauthAccess(getToken())))
 		}
+	} else {
+		opts = append(opts, grpc.WithInsecure())
 	}
 	conn, err := grpc.Dial(serverAddr, opts...)
 	if err != nil {