The CNN/ORC International survey released Monday indicated Romney's favorable rating among Americans has jumped from 34 percent in February to 48 percent now.
Forty-two percent of Americans said they view the presumptive Republican presidential nominee in a negative light.
Obama has a 56 percent favorable rating in the latest CNN/ORC International poll. Forty-two percent said they have an unfavorable opinion of Obama. The president's favorable and unfavorable ratings are unchanged from similar polls in March and April.
The survey also indicated Obama has a 49 percent-to-46 percent edge over Romney in the overall race for the White House. The gap is within the survey's sampling error, meaning the battle for the presidency is basically tied, CNN said.
Results are based on nationwide telephone interviews with 1,009 adults, including 895 registered voters, conducted last Wednesday and Thursday. The margin of error is 3 percentage points for the overall sample and 3.5 percentage points for registered voters.