diff --git a/src/objective-c/GRPCClient/GRPCCall.m b/src/objective-c/GRPCClient/GRPCCall.m
index 60a946a472c..7e0640e8ae1 100644
--- a/src/objective-c/GRPCClient/GRPCCall.m
+++ b/src/objective-c/GRPCClient/GRPCCall.m
@@ -103,7 +103,7 @@ const char *kCFStreamVarName = "grpc_cfstream";
   /** Serial dispatch queue for tasks inside the call. */
   dispatch_queue_t _dispatchQueue;
   /** Flags whether call has started. */
-  bool _started;
+  BOOL _started;
 }
 
 - (instancetype)initWithRequestOptions:(GRPCRequestOptions *)requestOptions