The new deal will keep Lahm at Bayern Munich until the summer of 2016.
Bayern Munich chairman Karl-Heinz Rummenigga has confirmed the new deal for Lahm, who joined the Bundesliga side as a 12-year-old.
“We have agreed on a new contract until 2016 with Philipp Lahm and it will be signed in the coming days,” Rummenigge told Bild newspaper.