Rival toy giants Hasbro Inc. and Mattel Inc. , were both hoping Friday to make money from the hugely successful Harry Potter children's books, which have sold over 18 million in the United States alone.

Time Warner Inc.'s Warner Bros. Worldwide Consumer Products unit, which owns the licensing rights to British author J.K. Rowling's books about a boy wizard, signed a deal with Hasbro to market Harry Potter trading cards and trading card games, role playing games, candy and electronics.

Mattel, home of Barbie dolls and Hot Wheels, signed a similar licensing deal to sell other Harry Potter items such as figures and board games.

Terms of neither deal were revealed.

Warner Bros. meanwhile is hoping to bring the adventures of the boy with the magical touch to the big screen next year. Director Steven Spielberg, who has made films for children such as "E.T." and "Hook" — his version of the Peter Pan story — is reported to be considering adapting "Harry Potter and the Sorcerer's Stone."

The announcement of Harry Potter tie-in deals came as the Toy Manufacturers of America trade group said toys based on licensed properties — a key profit generator for show business — have posted impressive growth in recent years. Their share of the overall toy market climbed to 46 percent in 1999 from 35 percent in 1996, the group said at the New York Toy Fair.

Such is Warner Bros.' confidence it can reap profits translating the success of the books into film and toys that its lawyers have been warning dozens of unofficial "Harry Potter" websites recently against unlawful use of the name.

"The challenge is...how they'll keep the excitement going until the first movie comes out," toy industry consultant Chris Byrne told the New York Daily News.

The Hasbro and Mattel products are expected to be available later this year initially only in Warner Bros. studio stores. They should be in other stores by the Christmas season and Warner hopes that will build demand for the movie, tentatively due in May 2001.

"Our intent is to judiciously roll out the product and not flood the market," Dan Romanelli, Warner Bros. Worldwide Consumer Products president, said in a statement. "We're looking to support the literary and film property as a long-term franchise.

"Strategies and timing will be determined on a market-by-market basis. In the U.S. and U.K., the product launch will be concurrent."

For Mattel, the world's largest toy maker, the Harry Potter deal could be a godsend. It has been struggling to climb out of a slump after its $3.5 billion acquisition last year of the software developer Learning Co. And last week, the company's chairwoman and chief executive Jill Barad resigned after Mattel posted an $18.4 million loss for its latest quarter.

The company's share price took a dive in September and has been hovering near its 52-week low of $10. It was up 9/16 at midday Friday at 10-13/16. Hasbro shares were up on the New York Stock Exchange at 15-3/16 after closing at 15 Thursday.

"The millions of Harry Potter fans around the world are going to love seeing literary references to things like cards and candy come alive through our exciting range of offerings," said Alan Hassenfeld, Hasbro's chairman and CEO. "We are thrilled that Warner Bros. Worldwide Consumer Products has selected Hasbro to bring the magic into new and exciting worlds."

"All of Mattel is inspired by J.K. Rowling's rich, magical world of Harry Potter and we're thrilled about the relationship," said Adrienne Fontanella, president of Mattel's Girls Products division.

"We are dedicated to ensuring that everything we create, from dolls and games to high-tech toys, will bring the characters to life in amazing new ways."

Warner Bros. Pictures signed with Rowling last year a deal that gave the company exclusive licensing and merchandising rights. The deal includes development of two films based on the first two books — "Harry Potter and the Sorcerer's Stone" and "Harry Potter and the Chamber of Secrets."