Image: Sen. Obama campaigning in Des Moines,Iowa. Credit: Joe Crimmings Photography/flickr
The Illinois senator picked up enough delegates from the final two primaries in Montana and South Dakota and gains in superdelegates to give him the win, making him the first African-American to lead his party.
There was no immediate sign of concession from Sen. Hillary Clinton though, who told supporters at a rally that she would be making no decisions on her future tonight.
However she has pledged to "to do what it takes" to get the Democratic nominee in the White House in November, a sign she may be interested in the job as Obama's running mate.
Sen. Obama has described the event as a "defining moment for our nation".
