diff --git a/packages/grpc-native-core/index.d.ts b/packages/grpc-native-core/index.d.ts
index 841da737f..718f6bdb4 100644
--- a/packages/grpc-native-core/index.d.ts
+++ b/packages/grpc-native-core/index.d.ts
@@ -579,7 +579,7 @@ declare module "grpc" {
      *   These options only have any effect when passed at the beginning of
      *   a client request.
      */
-    setOptions(options: MetadataOptions);
+    setOptions(options: MetadataOptions): void;
   }
 
   export type MetadataValue = string | Buffer;