Markey to run for Kerry's Senate seat in Mass.
Recent events including superstorm Sandy, the mass shooting at Sandy Hook Elementary School in Connecticut and the showdown over the fiscal cliff "have all made clear that Massachusetts needs a senator with the right priorities and values," Markey said in a statement on Thursday.
"I have decided to run for the U.S. Senate because this fight is too important," he added.
Markey, 66, has held his seat in the House of Representatives since 1976 and is the ranking member of the Natural Resources Committee.
Markey's bid for Kerry's seat, which the senator has held since 1985, could get a big boost from Massachusetts Gov. Deval Patrick, who has authority to appoint an interim senator to serve from the time Kerry steps down until the special election about five months later.
The outcome of the race would not tip the balance of power in the Senate, where Democrats currently enjoy a 55-45 majority.
Sen. Scott Brown, a Republican who lost his seat in November to Democrat Elizabeth Warren, has not said whether he will now run for Kerry's seat. Brown, 53, who came to the Senate in 2010 after winning a special election to complete the term of the late Sen. Ted Kennedy, will conclude his term when Warren is sworn in next week.
Brown, however, has hinted he could consider another run, saying in his farewell speech on the Senate floor, "We may obviously meet again."