1. Open a Web browser and go to the Google AdSense help page. Sign in to your account if you are not yet signed in.
2. Click the link labeled 'I Want To Permanently Cancel My Account.' This opens a page that contains a link to the form you must fill out and other information, such as final payment details, you should read before cancelling your account.
3. Read the cancellation terms and conditions, then click the 'Cancellation Form' link.
4. Fill out the online cancellation form by entering your contact information and answering the security questions. You must provide AdSense account information such as your AdSense login email, your publisher ID and the date your account first registered impressions. Find this information on your AdSense account page. Click 'Submit.'