The satirical ad shows images of convicted financiers, including Bernie Madoff and Enron's Ken Lay, and suggests Romney thinks Big Bird is behind their crimes.
The Republican hopeful said in last week's debate that he would end subsidies to PBS as a way to cut federal spending, even though he likes Big Bird.
Obama's ad pokes fun at that assertion, saying Romney "knows it isn't Wall Street you need to worry about, it's Sesame Street."
Republicans say the ad shows Obama is focusing on inconsequential matters rather than more urgent issues like the economy and the Middle East.
(Copyright 2012 by The Associated Press. All Rights Reserved.)