The city is buying 33,000 trash cans - about one for every 10 rats in the city - and giving them to residents in four poor neighborhoods where the rodents are a big problem.

The Board of Estimates approved $200,000 yesterday to buy the cans, which Rubbermaid is selling to the city at cost - $6 a can, about a quarter of their retail price.

"This is a rat restaurant," Mayor Martin O'Malley said at a morning news conference as he uncovered a rusted metal can coming apart at the seams.

"And this is a fortification against rats," he added, showing off one of the new cans: a 32-gallon plastic receptacle with a hinged lid and the Baltimore Believe logo on one side.

The cans will be distributed in Oliver, Sandtown/Winchester, Washington Village and central Park Heights during the spring. Before then, workers will go door to door to encourage residents to put trash in cans instead of bags, which rats and other animals can easily chew through.

Baltimore had more rats than people five years ago, when the number of rats was estimated at 700,000 and the human population was about 657,000.

Now the number of rats is down to about 320,000, a reduction city officials credit to the stepped-up efforts of the Rat Rubout crew, sanitation police and the environmental control board.

Residents registered 600 rat complaints a week with the city in 1997, said Kurt L. Kocher, spokesman for the Department of Public Works. Today, the number is about 100 a week.