From ITwiki

Contents 1 Via Terminal 1.1 To find your "Wired" MAC Address 1.2 To find your "Wireless" MAC Address 2 Via Graphical User Interface 2.1 Open System Preferences 2.2 Select Network 2.3 Select Device 2.4 Wireless 2.5 Wired

Via Terminal

To find your "Wired" MAC Address

To find your wired MAC address, type the following into a terminal window

ifconfig en0 | grep ether

To find your "Wireless" MAC Address

To find your wireless MAC address, type the following into a terminal window

ifconfig en1 | grep ether

Via Graphical User Interface

Open System Preferences

Open System Preferences.

Select Network

While in System Preferences select the Network icon.

Select Device

In the window that appears, highlight the device you wish to find the physical address for and click Advanced.

Wireless

Your Wireless MAC Address is labled as the Airport ID.

Wired

1. To locate your Wired MAC address, back up to the "Select Device" screen and highlight "Ethernet" in the right-side panel.
2. Click "Advanced" near the bottom left, then click the Ethernet tab ('Hardware' in Lion).
3. Once there, your MAC Address is labeled as the Ethernet ID ('MAC Address' in Lion).