This is one of the most asked questions on Google - How can I see the list of friends who unfriended me on Facebook? May be facebook doesn't provide this feature just because it assumed that people normally don't care about who ignore them being facebook provides lot of other features. Actually the fact is reverse. People are always curious to get something which doesn't exist yet, lol.
While people looking for the existence of such features, some good geeks came forward and implemented an application which provides this option.The application is basically an add-on or extension for your browsers which lets you find your 'lost friends' while using facebook in chrome or firefox browser.
Google chrome users can get the extension from here -
Firefox users can get the add-on from here - http://formybrowser.com/unfriend-notify
Please follow the list of steps below to see who unfriended you:-
1) Please install the above extension in your browser and access your facebook profile from the same browser.
2) Click 'Friends' tab from the profile page to see the list of friends. Now you will see something new, right? Yes there will be a new menu item "Lost Friends".
3) By clicking "Lost friends" link, you can see all those people who unfriended you. Please keep note of them in case you never want add them in future, lol.
Please try it out and let us know your feedback in the comments section below. You can also post here if you know any other useful tricks to find lost friends on facebook.