diff --git a/AFNetworking/AFHTTPClient.m b/AFNetworking/AFHTTPClient.m
index fe18b2c..6d47148 100644
--- a/AFNetworking/AFHTTPClient.m
+++ b/AFNetworking/AFHTTPClient.m
@@ -366,6 +366,7 @@ static void AFNetworkReachabilityReleaseCallback(const void *info) {}
     if (_networkReachability) {
         SCNetworkReachabilityUnscheduleFromRunLoop(_networkReachability, CFRunLoopGetMain(), (CFStringRef)NSRunLoopCommonModes);
         CFRelease(_networkReachability);
+        _networkReachability = NULL;
     }
 }