Arthur Ashe, the extraordinary Wimbledon and U.S. Open champion who had hoped to compete in those tournaments again after suffering a heart attack and undergoing quadruple bypass surgery, officially announced his retirement from competitive tennis yesterday at age 36.

"It is time. Health is a factor, but that's not the only reason," Ashe, a Renaissance man among athletes, told reporters before delivering a lecture at San Francisco State University.

"I feel pretty good," he said. "My doctors say I will live to be 100, but they won't put that in writing."

His public announcement followed a letter that Ashe sent to friends and business associates, dated April 11 announcing that his days as a playing pro were over and that he is available for other assignments.

"Long ago in my Sunday School classes, I learned that 'for everything there is a season,'" Ashe wrote." . . . After many hours of hard thought and soul-searching, I have decided from today on, to end my nonstop globetrotting odyssey in search of the perfect serve and retire from competitive tennis. In its place, I hope to begin another exciting season of writing, talking, listening, reading and assisting. . . ."

Ashe is the only black man to have won the world's major tennis titles, including the first U.S. Open (1968), the Australian Open when it still meant something (1970), and Wimbledon (1975), where his memorable upset of defending champion Jimmy Connors was one of the most popular victories ever.

A self-proclaimed "citizen of the world," thoughtful and knowledgeable on numerous subjects, Ashe has long been respected as much for his sportsmanship, eloquence, and deportment as for his electric serve and backhand. In a sport overpopulated with crybabies and greedy opportunists, he became a millionaire without ever forgetting his sense of responsibility to the public and the game.

Ashe has no shortage of business opportunities. He is under contract to ABC-TV as a commentator and writes a syndicated sports column for The Washington Post. He has lucrative endorsement contracts for clothing, rackets and other products, and personal services contracts with several companies.

However, until experiencing chest pains while making a routine training run in Egypt last month, Ashe expected to resume his playing career this spring. He considered this a personal medical challenge.

The sports world was shocked when Ashe -- who never smoked, seldom drank, and was lean and fit at 6-1 and 155 pounds -- suffered a mild heart attack last July 31, three weeks after his 36th birthday, while conducting a charity tennis clinic for fellow pro Vitas Gerulaitis.

On Dec. 14, he underwent a three hour bypass operation to relieve blockages around four arteries. Eight days later, in a hospital press conference in New York, he predicted he would be playing at Wimbledon this June.

He resumed light training, but knew after his experience in Egypt that his competitive days were probably over. The episode alarmed him, but tests showed that the problem was not serious.

He didn't want to rule out playing again until absolutely necessary, recalling that he had made an unlikely comeback following delicate heel surgery in February 1977. After a year's layoff, he climbed from No. 257 in the computerized world rankings back to No. 7, and reached the final of the Grand Prix Masters in January 1979.

Asked last month why he wanted to pay the price of another comeback, he said: "Because I love playing tennis and I'm one of the best in the world at it. Nobody asks the seventh best doctor or lawyer in the world why they want to keep at their profession, even if they were the very best once."

Ashe was ranked No. 1 in the world in 1975. In addition to his three victories in Grand Slam events i singles, he won the Australian and French Open Doubles, the WCT singles in 1973, the U.S. Clay Court and Hard-Court singles, and was a member of the U.S. Davis Cup team for 10 years, leading it to victory in 1968.