The poll indicated Romney leads Obama 49 percent to 47 percent among likely voters.
The poll comes one day after the Pew poll showed Romney with a 49-45 edge over the president, while a United Press International poll had Obama ahead by 1 point.
Gallup showed Obama leading 49-46 among registered voters, while Pew had the two candidates tied at 46-46 and UPI had Obama up 49-46 among registered voters.
Although the Gallup poll showed Romney in the lead following last week's debate in Denver, it also showed 53 percent of those surveyed said they approve of Obama's performance in office, compared to 42 percent who said they disapprove.
The Gallup poll was conducted Oct. 2-8. The Princeton, N.J., pollster surveyed 3,214 registered voters and 2,721 likely voters by phone nationwide. The poll's margin of error is 2 percentage points.