diff --git a/AFNetworking/AFJSONRequestOperation.m b/AFNetworking/AFJSONRequestOperation.m
index a7e9a68..fffc60c 100644
--- a/AFNetworking/AFJSONRequestOperation.m
+++ b/AFNetworking/AFJSONRequestOperation.m
@@ -70,7 +70,7 @@ static dispatch_queue_t json_request_operation_processing_queue() {
 
         // Workaround for behavior of Rails to return a single space for `head :ok` (a workaround for a bug in Safari), which is not interpreted as valid input by NSJSONSerialization.
         // See https://github.com/rails/rails/issues/1742
-        if ([self.responseData length] > 0 && self.responseString && ![self.responseString isEqualToString:@" "]) {
+        if (self.responseString && ![self.responseString isEqualToString:@" "]) {
             // Workaround for a bug in NSJSONSerialization when Unicode character escape codes are used instead of the actual character
             // See http://stackoverflow.com/a/12843465/157142
             NSData *data = [self.responseString dataUsingEncoding:NSUTF8StringEncoding];