You can find your serial number in several places:
In Mac OS X
On most computers with Mac OS X, you can find the serial number in the About This Mac window.
On the surface of the computer
Unplug all cords and connectors from your Mac mini, then turn it over.
On Mac mini (Mid 2010 and later) computers, the serial number is printed on the metal frame without a bar code:
On Mac mini (Original) to Mac mini (Late 2009) computers, the serial number and Ethernet ID number with bar codes are on a label on the edge of the bottom housing of the computer (below).
On the original product packaging
If you still have the original packaging for your Mac mini, you can find the serial number on the barcode label that is affixed to the packaging.
On the original receipt (or invoice)
Some retailers may include the serial number of your Mac mini on the receipt.
Learn how to find the serial number of other Apple hardware products.