Priorities USA Action is airing the ad in Colorado, Florida, Ohio, Pennsylvania and Virginia. It comes a day after the Obama campaign released a similar ad attacking Romney's past role as head of private equity firm Bain Capital.
The new Priorities ad shows a testimonial from a former steel worker at GST Steel in Kansas City, Mo., who says Romney's Bain Capital was only interested in making money at the expense of workers.
Romney's campaign has said it welcomes the debate on jobs.
Eric Fehrnstrom, a senior Romney adviser, said Tuesday the ad on Bain Capital was an attempt to distract voters from Obama's poor economic record and was "the biggest smokescreen since Mount St. Helens."