Federer, 32, who withdrew from the Madrid Open to be with his wife Mirka, took to Twitter to declare that his happy family now includes twin boys Leo and Lenny.
He also has twin daughters Myla and Charlene, who were born in 2009.
He wrote: "Mirka and I are so incredibly happy to share that Leo and Lenny were born this evening! #TwinsAgain #Miracle".
Federer's friends from the tennis world served up warm congratulations on Twitter about the new arrivals.
Former tennis player Boris Becker tweeted: "Congrats to Mirka and @rogerfederer on the new addition to the #family ! #Leo and #Lenny will partner perfectly their older sisters in mixed."
Belgian former world number one Kim Clijsters tweeted "congrats to the family!! Great names!!!", while American John Isner said that he was "thinking future tag team champs for his second set of twins".
World number six Tomas Berdych added: "Roger has done it again!!!well done and all the best for the family!!#twins".