Pawlenty told supporters on a conference call Sunday morning that he would announce on ABC's "This Week" that he was ending his campaign after a disappointing finish in the Iowa straw poll on Saturday.
The poll was a test of organizational strength and popularity in the state whose caucuses lead off the GOP nomination fight.
Pawlenty had struggled to gain traction in Iowa, a state he had said he must win, after laying the groundwork for a campaign for nearly two years.
He's been eclipsed in polls in recent months by his Minnesota rival, Rep. Michele Bachmann. She won the straw poll on Saturday.