diff --git a/cocoa/src/appkit.rs b/cocoa/src/appkit.rs
index c30b1f5..76ec48d 100644
--- a/cocoa/src/appkit.rs
+++ b/cocoa/src/appkit.rs
@@ -478,7 +478,12 @@ pub trait NSRunningApplication: Sized {
     unsafe fn currentApplication(_: Self) -> id {
         msg_send![class!(NSRunningApplication), currentApplication]
     }
+
     unsafe fn activateWithOptions_(self, options: NSApplicationActivationOptions) -> BOOL;
+
+    unsafe fn runningApplicationWithProcessIdentifier(_: Self, pid: libc::pid_t) -> id {
+        msg_send![class!(NSRunningApplication), runningApplicationWithProcessIdentifier:pid]
+    }
 }
 
 impl NSRunningApplication for id {