 <p>You would have to have the @interface and @implementation have the same class name. Aside from that, it does not matter what file the @interface or @implementation is in as long as the @interface is accessable from the file the @implementation is in (in the same file or <code>#import</code>ed.</p> <p>So in your case, if you did <code>@interface ReceiverViewController...</code> you would be fine.</p>