A Canadian-based conglomerate intent on rewriting the economic rules of thoroughbred racing agreed yesterday to buy Pimlico Race Course and Laurel Park.

Magna Entertainment Corp. will acquire a 51 percent stake in the Maryland Jockey Club, the umbrella organization for the two racetracks as well as a training center in Bowie, and will have a right to buy the rest.

Jockey Club President and majority owner Joseph A. De Francis and his sister, Karin De Francis, will remain at the helm of the company, with day-to-day control under five-year management agreements.

They will also hold 49 percent of the voting stock in the operation, though the deal provides for a possible buyout of their interest in the fifth year. Joseph De Francis will be nominated for a seat on the Magna board of directors.

"We could not be more thrilled," said Joseph De Francis, who inherited the tracks upon the death of his father, Frank, in 1989. "This is the right thing to do for the Maryland Jockey Club and for Maryland racing. You look down the road and see what is happening in racing and you can't remain a mom-and-pop island."

The deal, which is subject to approval by the state, values the enterprise at $117 million. Only about half of that amount will change hands at closing because Magna isn't buying all of the stock at first and will assume $30 million in debt.

Magna, based in Aurora, Ontario, just north of Toronto, has assembled the largest chain of racetracks in the world in just four years. The combined operation, which includes California's Santa Anita Park and Florida's Gulfstream Park, account for about 25 percent of all thoroughbred wagering in North America. It is also building a track in Austria.

Led by strong-willed auto-parts magnate Frank Stronach, Magna has bet heavily on a coming revolution in racing, one that will see more fans watching and wagering on races over their desktop computers and on specialty television networks. Magna owns an Internet wagering service, XpressBet, and is backing a satellite- and cable-TV start-up dedicated to racing.

Laurel and Pimlico, home of the Preakness Stakes, provide a needed boost in Magna's holdings, filling a summer and fall gap in its racing calendar when many of its other tracks aren't running live meets. The two Maryland tracks run 220 days of live racing a year.

One of the oldest names in sports, the Maryland Jockey Club was founded in 1743. Among its early fans was President George Washington, who attended meets in Annapolis. It employs about 900 and holds the Preakness, which remains one of the biggest events in the sport and is the second installment of the Triple Crown series that begins each spring with the Kentucky Derby.

Jim McAlpine, president of Magna Entertainment, promised improvements to the tracks and training center consistent with his company's vision of racetracks as "total entertainment" centers that draw new fans to the sport. That could mean concerts and shops at the tracks and possibly even lights for night racing.

"Basically we should build on the successful experience of places like Vegas, where they took gaming, in our case parimutuel wagering, and they combined it with world class entertainment and shopping experiences for their customers," McAlpine said.

He said it is too soon to be specific on the improvements but said the Preakness would remain at Pimlico, in Baltimore. "One of our first priorities is to make Pimlico a better home for the Preakness," he said.

Magna supports slot machines at racetracks, and will lobby for it, but thinks racing can thrive on its own. Only one of its tracks, a harness operation in Canada acquired this year, has slot machines.

"We are first and foremost a racing company," McAlpine said.

Baltimore Mayor Martin O'Malley said Magna's takeover "could mean great things."

"When you have a player like Magna, which has ownership of so many tracks and seems to have some pretty deep pockets, they're not afraid to make long-term investments."

With the purchase of Laurel and Pimlico, Magna will either own, lease or have agreements in place to buy 14 racetracks in the United States and Canada. The company, whose stock is traded on the NASDAQ, made a profit of $13.5 million last year on revenues of $519 million, compared with a profit of $441,000 on revenues of $413.6 million the year before.

The company's stock was trading at $6.05 last night, down 39 cents over the day.