When calling Apple Support or your local Apple store, you may be asked for the serial number of your Mac OS X. You can use the “About This Mac” window to find your computer’s serial number when started up from Mac OS X.

Follow these steps:

  1. Choose About This Mac from the Apple Menu.
  2. Double-click the version text, for example “Version 10.4”.

Your computer’s serial number now appears where the version text had been.