diff --git a/AFNetworking/AFJSONUtilities.m b/AFNetworking/AFJSONUtilities.m
index 51241cf..83bb849 100644
--- a/AFNetworking/AFJSONUtilities.m
+++ b/AFNetworking/AFJSONUtilities.m
@@ -48,7 +48,9 @@ NSData * AFJSONEncode(id object, NSError **error) {
         
         NSUInteger serializeOptionFlags = 0;
         [invocation setArgument:&serializeOptionFlags atIndex:2]; // arguments 0 and 1 are self and _cmd respectively, automatically set by NSInvocation
-        [invocation setArgument:error atIndex:3];
+        if (error != NULL) {
+            [invocation setArgument:error atIndex:3];
+        }
         
         [invocation invoke];
         [invocation getReturnValue:&data];
@@ -99,7 +101,9 @@ NSData * AFJSONEncode(id object, NSError **error) {
         [invocation setArgument:&object atIndex:2]; // arguments 0 and 1 are self and _cmd respectively, automatically set by NSInvocation
         NSUInteger writeOptions = 0;
         [invocation setArgument:&writeOptions atIndex:3];
-        [invocation setArgument:error atIndex:4];
+        if (error != NULL) {
+            [invocation setArgument:error atIndex:4];
+        }
 
         [invocation invoke];
         [invocation getReturnValue:&data];