More than 50 per cent of the electorate turned out for the vote, a much higher proportion than is typical in a by-election.
Mr Galloway, who has worked as a presenter for Iranian channel Press TV, previously served as a Respect MP for Bethnal Green and Bow, but was defeated at the last general election. Before then he was a Labour MP, elected in Scotland in 1987, but he was expelled from the party in 2003 after his outspoken attacks on Tony Blair and the war in Iraq.
The Labour Party had held the Bradford West seat since 1983.
Mr Galloway said it was “a very comprehensive defeat for New Labour” and “a pathetic performance by the Government parties”.
He told Sky News: "The people of Bradford have spoken this evening for people in inner cities everywhere in the United Kingdom."
He also wrote on Twitter after his victory: "Long live Iraq. Long live Palestine, free, Arab, dignified."
