A federal judge has told the maker of one of the nation's best-selling peanut butters -- Skippy -- it won't have to change its brand name because there was once a comic strip with the same name.

District Court Judge Oren R. Lewis rejected a Reston firm's claims to the name "Skippy" and gave a New Jersey company permission to keep the name on its peanut butter jars.

Skippy Inc., a firm controlled by the daughter of a cartoonist who drew a comic strip called "Skippy" in the 1920s and 1930s, had challenged CPC International Inc.'s use of the name in a lawsuit filed in federal district court in Alexandria. The suit alleged that the peanut butter brand name infringed on the Virginia company's trademark.

Lewis rejected the claim, saying that the Englewood Cliffs, N.j., firm is entitled to continue using the name on the peanut butter products it has marketed since 1933. CPC International and its predecessors have marketed the food for decades, and have never claimed that the peanut butter was endorsed by the comic-strip character, Lewis ruled.

In the lawsuit Reston businesswoman Joan Crosby Tibbetts said that the name "Skippy" was coined by her late father, Percy L. Crosby, for a cartoon strip character he created in 1923. Her Reston firm said in its suit that it still maintains it has exclusive use of the name and manufactures pens, pencils, dolls, and other items that portray Crosby's ragamuffin character.

However, in his 14-page opinion, Lewis ruled that similarity of name alone was insufficient to show trademark violation. He also denied Tibbetts' request for an injunction against the New Jersey-based company, and for unspecified financial damages.

"I plan to vigorously appeal the ruling," Tibbetts said yesterday, a spokesman for the New Jersey firm said it was delighted with Lewis's ruling and would contest any appeal.