If you can't beat 'em, launch your own merchandise line.

The Texas Transportation Department, holder of the trademark on the catchphrase "Don't Mess With Texas," has entered into a licensing agreement to sell hats, mugs, T-shirts and other merchandise emblazoned with the slogan.

For years, the department's lawyers have been busily chasing down dealers of unauthorized "Don't Mess With Texas" gear.

Direct Mark of San Marcos will have the exclusive right to produce the merchandise, and the state agency will receive 8 percent of the sales for use in an anti-littering campaign.

The T-shirts, mugs and hats are already being offered on the campaign's Web site. The merchandise will probably be found soon on store shelves, too.

"We hope to have the opportunity to take some royalties off those products and put it back into litter prevention," said Doris Howdeshell, director of the department's travel division.

"Don't Mess with Texas" was created by an Austin advertising firm in 1986 and made its TV premiere during the 1987 Cotton Bowl game for use in the anti-littering campaign.

As the pugnacious slogan grew more popular, appearing on everything from breath mint tins and refrigerator magnets to T-shirts, the Transportation Department decided in 2000 to register it as a trademark.

The department recently stepped up enforcement to protect it. Over the past year and a half, about 30 cease-and-desist letters have gone out to merchandisers, but no lawsuits have been filed.

"We will continue to send cease-and-desist letters when we find out a retailer is actually selling an unauthorized product, but it's not like we have a full staff of attorneys taking care of these," Howdeshell said.