Sam Jaffe, 55, a former Moscow and Hong Kong bureau chief for ABC News who won a court ruling last year clearing him of allegations that he had spied for the Soviet Union, died of cancer Feb. 8 at his home in Bethesda.

In the 1950s and 1960s, Mr. Jaffe had a brilliant run as a newspaper and broadcast journalist. His assignments took him from New York to Siberia to the jungles of Southeast Asia and they gained him a standing enjoyed by few in his profession.

As it turned out, those promising times were an incongruous prelude to the shadows that followed him afterwards. For most of the past 15 years Mr. Jaffe had engaged in a tenacious and ultimately successful effort to clear his name of insubstantial but persistent suggestions by the FBI and the CIA that he was a foreign agent. The origin of these claims -- many of which are still classified "secret" -- has never been entirely explained.

"The last nine years have been incredible," Mr. Jaffe said in an interview with The Washington Post in 1979. "If it weren't for a few friends, I would be broken . . . . I say I am not a Russian spy. The FBI says, 'Yeah, you are.' Well, I want them to prove it. I want it all out in the open. I want my family cleared. If I should drop dead, I don't want them living with this stigma. The CIA has cleared me. Now I want the FBI to do the same."

Earlier, Mr. Jaffe's relations with the FBI had been cordial. In 1976 he disclosed that for several years beginning in the 1950s he had reported to the agency on his Russian contacts.

Mr. Jaffe never was formally charged with espionage. But he contended that U.S. intelligence agencies had conspired to deprive him of his livelihood on the ground that he was a security risk. With the help of the American Civil Liberties Union, he sought relief in the courts under the Freedom of Information Act.

Last year, U.S. District Judge Barrington D. Parker issued an opinion saying that the FBI had no grounds for questioning Mr. Jaffe's patriotism. In the late 1970s, the CIA said in a letter to Mr. Jaffe that its own investigation had shown him to be a loyal citizen.

The years of dull effort that it took to reach this result were in stark contrast to Mr. Jaffe's earlier career. A man who was as cheerful and disarming as he was resourceful and aggressive, he had a happy talent for being in the right place at the right time.

In 1955, as a freelancer, he covered a conference of Third World countries at Bandung, Indonesia, and interviewed the late Premier Chou En-lai of China. As a correspondent for CBS from 1955 to 1961, he covered the United Nations and Soviet Premier Nikita S. Khrushchev's visit to this country in 1959.

In 1960, he went to Moscow for CBS to cover the trial of Francis Gary Powers, the pilot of the U-2 spy plane that was shot down over the Soviet Union in May of that year. The incident led to the cancellation of a summit meeting between Khrushchev and President Dwight D. Eisenhower and was one of the most publicized incidents of the Cold War.

Mr. Jaffe was the only western newsman covering the trial who was permitted by Soviet authorities to sit on the same level of the courtroom as Powers. He also was quartered in the same hotel as Powers' wife, who went to Moscow for the proceedings. In the Moscow context, these circumstances gave Mr. Jaffe a slight but nonetheless important advantage over his competitors.

In 1961, Mr. Jaffe joined ABC and went to Moscow to open its first bureau there. He covered the Cuban missile crisis in 1962, the signing of the atmospheric nuclear test ban treaty, and the thaw in the Cold War. He was among the first -- some said he was the very first -- to report the ouster of Khrushchev from politics on the night of Oct. 14-15, 1964.

In 1965, he was expelled from the Soviet capital because of a report ABC carried from Washington saying that another shake-up in the Soviet leadership was imminent.

By then, Mr. Jaffe already had been assigned to take over ABC's Hong Kong Bureau. As the war in Vietnam deepened, he was sent there and for his coverage he won a prize from the Overses Press Club. In 1968, he was reassigned to the United States and moved to Washington. The following year he resigned from ABC.

In 1972 and again in 1974, he made trips to China as a freelance correspondent for United Press International and the Chicago Tribune. He had a weekly talk show on WRC Radio in the late 1970s. Unable to find regular work in the news business in recent years, he had assisted his wife in her flower business.

Samuel Adason Jaffe was born in San Francisco. He served in the Merchant Marine in World War II and then the Navy Reserves. He was a Marine combat correspondent in Korea during the war there. He attended the University of California at Berkeley, Columbia University and the New School for Social Research.

He worked for the old International News Service in San Francisco. He worked briefly for the U.N. in the early 1950s and then joined Life Magazine, where he was a reporter from 1952 to 1955.

Mr. Jaffe, who lived in Bethesda, was a member of the Council on Foreign Relations, the Overseas Writers, the White House and State Department correspondents associations, and the Marine Corps Combat Correspondents Association.

His marriage to the former Josephine Winters ended in divorce.

Survivors include his wife, Jeune, and their two daughters, Deborah and Leah, all of Bethesda, and two children by his first marriage, Linda Franklin of Katonah, N.Y., and David Jaffe of New York City.