diff --git a/packages/grpc/src/comsumer/clients.ts b/packages/grpc/src/comsumer/clients.ts
index 00e422b0be9..beb41169de6 100644
--- a/packages/grpc/src/comsumer/clients.ts
+++ b/packages/grpc/src/comsumer/clients.ts
@@ -115,7 +115,9 @@ export class GRPCClients extends Map {
     let genericFunctionName;
     switch (genericFunctionSelector) {
       case 0:
-        options.metadata.set('rpc.method.type', 'unary');
+        if (! options.metadata.get('rpc.method.type')) {
+          options.metadata.set('rpc.method.type', 'unary');
+        }
         genericFunctionName = new ClientUnaryRequest(
           client,
           originalFunction,
@@ -123,7 +125,9 @@ export class GRPCClients extends Map {
         );
         break;
       case 1:
-        options.metadata.set('rpc.method.type', 'server'); // server streaming
+        if (! options.metadata.get('rpc.method.type')) {
+          options.metadata.set('rpc.method.type', 'server'); // server streaming
+        }
         genericFunctionName = new ClientReadableRequest(
           client,
           originalFunction,
@@ -131,7 +135,9 @@ export class GRPCClients extends Map {
         );
         break;
       case 2:
-        options.metadata.set('rpc.method.type', 'client'); // client streaming
+        if (! options.metadata.get('rpc.method.type')) {
+          options.metadata.set('rpc.method.type', 'client'); // client streaming
+        }
         genericFunctionName = new ClientWritableRequest(
           client,
           originalFunction,
@@ -139,7 +145,9 @@ export class GRPCClients extends Map {
         );
         break;
       case 3:
-        options.metadata.set('rpc.method.type', 'bidi'); // bidirectional streaming
+        if (! options.metadata.get('rpc.method.type')) {
+          options.metadata.set('rpc.method.type', 'bidi'); // bidirectional streaming
+        }
         genericFunctionName = new ClientDuplexStreamRequest(
           client,
           originalFunction,