The 31-year-old has signed a two-year contract with the Cottagers.
The Bulgarian striker will be reunited with Martin Jol, who managed Tottenham while Berbatov was at the club.
Berbatov told Fulham's official website: "I'm delighted to have signed for Fulham and I look forward to playing under Martin Jol once again.
"As soon as I was aware of Fulham's interest, my decision to join was an easy one to make.
"I'm impressed with the set up here and the people have made me feel welcome. There is a close and personal feel around the club and I can't wait to get started."
Jol said: "Dimitar is a player I've always admired. He did well for me at Spurs and I'm sure that he will do well here at Fulham.
"He's a player of great quality and technical ability who will give me the attacking option I've been looking for.
"When he's not scoring goals, his ingenuity often leads to chances being created for his team-mates and I'm delighted that we've been able to convince him to come to us, as there was a lot of attention from other clubs."