Obama received 58 per cent of the votes as opposed to Clinton's 41 per cent. "I am grateful to the people of Wisconsin for their friendship, their support and their tremendous sense of civic pride," The Washington Post quoted Obama, as saying in Houston. "The problem that we face in America is not a lack of good ideas, it's that Washington has become a place where good ideas go to die," he added.
Clinton will now be under intense pressure to break Obama's winning streak in Ohio and Texas next month.
Meanwhile, Republican presidential frontrunner Senator John McCain has defeated his rival Mike Huckabee in both Wisconsin and Washington State.
McCain secured 55 per cent of the votes as opposed to Huckabee's 37 per cent.