The campaign, announced Monday and the largest the company has run in years, will run on television, radio and the Internet. The ads will feature actor William Shatner, who has done previous commercials for Priceline.
The commercials will compare room rates available through Priceline with the rates offered at other online booking sites, such as Travelocity, Hotels.com and Expedia.com.
Priceline did not say how much it will spend on the campaign.
It's been a difficult year or so for travel Web sites. Fallout from the Sept. 11, 2001, terrorist attacks and cost cutting by airlines have made the business much more difficult. Hotels.com last week lowered expectations for its fourth quarter, for example, citing lower hotel occupancy and average daily room rates.
Priceline15 percent of its work force in November. It also posted weaker-than-expected third-quarter results, hurt by its airline-related operations. The company said at the time that it planned to focus more on the hotel business.