One of the ways Facebook seeks to grow users' connections with each other is to suggest friends they may know, but are not friends with, on the website. The Friend Finder Suggestion feature works through your e-mail address. When you register for a new account with Facebook, you can let Facebook search with your e-mail address for friends who are already signed up on the site. When you log in, Facebook generates the friend suggestions to which you can respond. Disable this information on the "Invites and Imported Contacts" page if you don't want this information to appear.
Sign in to your Facebook account with your e-mail address and password.
Click the "Home" tab, then click "Friends" in the left column of your screen.
Click the "Manage Imported Contacts" link under "Add Personal Contacts as Friends" in the centre of the screen.
Click the "Remove All Contacts" link below the "Manage Invites and Imported Contacts" page.
Click the blue "Remove" button. Facebook will process your request and send you a notification when it's completed.