How to Not Let People See Who You Are Friends With on Facebook
Facebook is what you make of it -- while some users want to share everything about their lives with the world, others choose to be considerably more private. Luckily, every aspect of your Facebook profile can be made either completely public or private. Many aspects of your profile can be kept from everyone but yourself, among them your Friend list. Editing your privacy settings to keep your Friend list hidden is a very quick process.
Click on the "Account" menu in the top-right corner of any Facebook screen and choose "Privacy Settings" from the menu.
Click the small blue "View Settings" link in the "Connecting on Facebook" section, at the top of the page.
Click on the gray square button to the right of the "See your friend list" and select "Customize" from the drop-down menu.
Click on the downward gray arrow next to the "Make this visible to these people" setting. Select "Only Me" from the drop-down menu.
Click "Save Changes" at the bottom of the window.