US Senator-elect Edward J. Markey officially resigned from his position as a US representative today in order to be sworn into his new job on Tuesday morning. His successor will be chosen by the voters of the Fifth Congressional District on Dec. 10, 2013.

Markey, a Malden Democrat who last month won a special election to fill the seat of John F. Kerry, is set to be sworn in on the floor of the US Senate by Vice President Joe Biden at 10 a.m.

Governor Deval Patrick said today he would be in Washington, D.C., on Tuesday as the state’s new junior senator takes his oath.

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State election law calls for a special election to be scheduled for a date between 145 and 160 days from when Markey resigns. Secretary of State William F. Galvin set the primary election for Oct. 15, with the general election to be held Dec. 10.

There are five Democrats currently running for the mostly suburban seat which runs from Winthrop to Woburn to Framingham to Holliston: State Representative Carl M. Sciortino of Medford, state Senators Will Brownsberger of Belmont, Katherine Clark of Melrose, Karen Spilka of Ashland, and Middlesex County Sheriff Peter J. Koutoujian of Waltham.

The district is heavily Democratic so the winner of the Democratic primary is the favorite to win the general election.