Lew Ayres, 88, an actor for nearly seven decades who was the original Dr. Kildare of the 1930s and who starred in the Academy Award-winning classic "All Quiet on the Western Front," died here Dec. 30. The cause of death was not reported.

Over the years, Mr. Ayres played opposite Greta Garbo and Jane Wyman and became identified as Dr. Kildare in the MGM film series. Shunned by the studios after he became a conscientious objector during World War II, he managed to revive his career and get an Academy Award nomination for "Johnny Belinda" in 1948.

In the 1990s, Mr. Ayres was still playing character roles in television dramas. Long a student of comparative religion, he toured the country with his documentaries about the faiths of all nations.

He was born Lewis Ayer in Minneapolis. He studied medicine at the University of Arizona. But the musical life appealed to him more, and he toured with bands, playing the banjo, piano and guitar. While playing in a Hollywood nightclub in 1928, he was discovered for films.

His first important role came opposite Garbo in her last silent film, "The Kiss." He followed that in 1930 with "All Quiet on the Western Front," Lewis Milestone's acclaimed war film from Erich Maria Remarque's novel. Mr. Ayres's role as the disillusioned young German soldier would be the most memorable of his career.

In 1938, he played the title role in a B picture, "Young Dr. Kildare," as a doctor in practice with the older Dr. Gillespie, played by Lionel Barrymore. The film made more money than many of MGM's major productions, and Dr. Kildare became a series character. Mr. Ayres and Barrymore made eight Dr. Kildare movies from 1939 to 1942.

When he was drafted into the military at 34, Mr. Ayres declined combat duty for religious reasons.

"You're finished in pictures!" roared his boss, Louis B. Mayer.

Pickets appeared at theaters playing Dr. Kildare films, and other theaters refused to book them. When Mr. Ayres did enter the military, he decided he would quit pictures afterward.

"Making movies seemed to me very trivial," the actor said in 1946. "But when I went overseas, I changed my mind. I realized how important movies are to the lives of so many people. Why, I even became a fan myself."

Mr. Ayres served for 3 1/2 years as a medic and a chaplain's aide in the Southwest Pacific theater, receiving three battle stars. His wartime service restored him to favor in Hollywood, and his first film back was "The Dark Mirror," opposite Olivia de Havilland.

"Johnny Belinda," in 1948, won Mr. Ayres an Academy Award nomination as best actor; he played the sympathetic doctor treating the raped deaf woman, the role that won Wyman an Oscar.

Later in his career, Mr. Ayres eased into character roles. When movie parts grew scarce, he went into television. He was offered the Kildare role in a series but declined when the network refused to agree to his request for no cigarette sponsorship.

"My feeling was that a medical show, particularly one that might appeal to children, should not be used to sell cigarettes," he explained later. Richard Chamberlain was given the role, and the program was a great hit.

A nondenominational Christian who had long studied the world's other religions, Mr. Ayres wrote a book, "Altars of the East," and followed with a five-part documentary in 1955. In 1976, he produced "Altars of the World," which won a Golden Globe Award as best documentary of 1976.

He once explained his purpose: "When man understands, he no longer fears; when he no longer fears, he loves; when he loves, there is peace."

His marriages to actresses Lola Lane and Ginger Rogers ended in divorce.

For 25 years, he lived an almost ascetic life, painting, studying and traveling. Then, in 1964, he married British airline flight attendant Diana Hall. They had a son, Justin, the actor's only child. CAPTION: LEW AYRES