diff --git a/src/node/ext/call.cc b/src/node/ext/call.cc
index 8cc3e38cd9513d78d8a055a00731132876a2d90c..15c9b2d97d6df4e6f37297a0e9d9e08005ac8c8b 100644
--- a/src/node/ext/call.cc
+++ b/src/node/ext/call.cc
@@ -550,6 +550,7 @@ NAN_METHOD(Call::StartBatch) {
     }
     uint32_t type = keys->Get(i)->Uint32Value();
     ops[i].op = static_cast<grpc_op_type>(type);
+    ops[i].flags = 0;
     switch (type) {
       case GRPC_OP_SEND_INITIAL_METADATA:
         op.reset(new SendMetadataOp());
diff --git a/src/php/ext/grpc/call.c b/src/php/ext/grpc/call.c
index 9f651ff56f69b71920b47771f4512bb3e542fde6..10a4946ea60da70ff8cd14645b0911e5a721622e 100644
--- a/src/php/ext/grpc/call.c
+++ b/src/php/ext/grpc/call.c
@@ -397,6 +397,7 @@ PHP_METHOD(Call, startBatch) {
         goto cleanup;
     }
     ops[op_num].op = (grpc_op_type)index;
+    ops[op_num].flags = 0;
     op_num++;
   }
   error = grpc_call_start_batch(call->wrapped, ops, op_num, call->wrapped);