You can easily sync your Mac’s Address Book contacts with your Google Contacts, here’s how to do it:

  1. Launch Address Book
  2. Click on the “Address Book” menu and select “Preferences”
  3. Click on the “Accounts” tab
  4. Select the “On My Mac” under the left accounts
  5. Check the checkbox accompanying “Synchronize with Google”
  6. Click on “Configure…”
  7. Enter your Google Account login, click “OK”
  8. Then click “Sync Now” from the menubar

Now your Address Book is synchronized with your Google contacts!

via OS X Daily.