Cumbria County Council has picked Balfour Beatty to rebuild a bridge swept away by floods in November 2009.
Cllr Tony Markley, the Cumbria county council cabinet member responsible for highways, said Balfour Beatty won an open tender with a £12m bid.
Local policeman PC Bill Barker was killed when the original bridge was swept away while he was directing traffic.
The A597 bridge in Workington was replaced temporarily by one built by the army, following the floods.
Northside Bridge, across the River Derwent in Workington, will open for traffic in May 2012.