How do I add sites to my filter list?

You can add up to 200 sites to your filter list. The URLs you enter into your filter list can be the actual URL of the website or the URL that is displayed on the ad for that website.

Log in to your account at https://www.google.com/adsense
Click Competitive Ad Filter under the AdSense Setup tab (for AdSense for search results pages)
Choose the appropriate product sub-tab
Click Add / Edit Sites
In the appropriate text box, enter the URLs of the sites whose ads you would like to filter from your site or AdSense for search results pages. Enter one URL per line.
Save your changes
Please note that it may take up to 3 hours for new URLs to be filtered from your pages.