diff --git a/AFNetworking/AFHTTPClient.m b/AFNetworking/AFHTTPClient.m
index 9383cc7..601baae 100755
--- a/AFNetworking/AFHTTPClient.m
+++ b/AFNetworking/AFHTTPClient.m
@@ -36,6 +36,10 @@
 #import <netdb.h>
 #endif
 
+#if __IPHONE_OS_VERSION_MIN_REQUIRED
+#import <UIKit/UIKit.h>
+#endif
+
 // Workaround for management of dispatch_retain() / dispatch_release() by ARC with iOS 6 / Mac OS X 10.8
 #if (defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && (!defined(__IPHONE_6_0) || __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_6_0)) || \
     (defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && (!defined(__MAC_10_8) || __MAC_OS_X_VERSION_MIN_REQUIRED < __MAC_10_8))
diff --git a/AFNetworking/AFURLConnectionOperation.m b/AFNetworking/AFURLConnectionOperation.m
index 49a6730..a743e29 100644
--- a/AFNetworking/AFURLConnectionOperation.m
+++ b/AFNetworking/AFURLConnectionOperation.m
@@ -25,6 +25,11 @@
 #import <UIKit/UIKit.h>
 #endif
 
+#if !__has_feature(objc_arc)
+#error AFNetworking must be built with ARC.
+// You can turn on ARC for only AFNetworking files by adding -fobjc-arc to the build phase for each of its files.
+#endif
+
 typedef enum {
     AFOperationPausedState      = -1,
     AFOperationReadyState       = 1,
diff --git a/README.md b/README.md
index ed5fe68..3d1a111 100644
--- a/README.md
+++ b/README.md
@@ -143,7 +143,17 @@ operation.outputStream = [NSOutputStream outputStreamToMemory];
 
 ## Requirements
 
-AFNetworking requires either [iOS 5.0](http://developer.apple.com/library/ios/#releasenotes/General/WhatsNewIniPhoneOS/Articles/iPhoneOS4.html) and above, or [Mac OS 10.7](http://developer.apple.com/library/mac/#releasenotes/MacOSX/WhatsNewInOSX/Articles/MacOSX10_6.html#//apple_ref/doc/uid/TP40008898-SW7) ([64-bit with modern Cocoa runtime](https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtVersionsPlatforms.html)) and above.
+AFNetworking 1.0 and higher requires either [iOS 5.0](http://developer.apple.com/library/ios/#releasenotes/General/WhatsNewIniPhoneOS/Articles/iPhoneOS4.html) and above, or [Mac OS 10.7](http://developer.apple.com/library/mac/#releasenotes/MacOSX/WhatsNewInOSX/Articles/MacOSX10_6.html#//apple_ref/doc/uid/TP40008898-SW7) ([64-bit with modern Cocoa runtime](https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtVersionsPlatforms.html)) and above.
+
+For compatibility with iOS 4.3, use the latest 0.10.x release.
+
+### ARC
+
+AFNetworking uses ARC as of its 1.0 release.
+
+If you are using AFNetworking 1.0 in your non-arc project, you will need to set a `-fobjc-arc` compiler flag on all of the AFNetworking source files. Conversely, if you are adding a pre-1.0 version of AFNetworking, you will need to set a `-fno-objc-arc` compiler flag.
+
+To set a compiler flag in Xcode, go to your active target and select the "Build Phases" tab. Now select all AFNetworking source files, press Enter, insert `-fobjc-arc` or `-fno-objc-arc` and then "Done" to enable or disable ARC for AFNetworking.
 
 ## Credits