Silvana Mangano, 59, the Italian actress whose role as a sensual country girl in the 1949 film, "Bitter Rice," made her a star, died yesterday at a hospital in Madrid. A hospital spokesman said Miss Mangano went into a coma Dec. 14 after suffering a heart attack during surgery for cancer. Film director Pier Paolo Pasolini once called her a "bitter beauty" who shone "like a pearl" but was always distant. In later years, her career was overshadowed by that of her husband of 34 years, movie producer Dino De Laurentiis. She was born in Rome. Her father was a Sicilian railroad worker and her English mother had been a dancer. Miss Mangano trained as a dancer and model. The former Miss Rome played only bit parts until she landed the starring role in director Giuseppe De Santis' "Bitter Rice," considered one of the best examples of the postwar Italian neo-realism movement. Filmgoers worldwide turned out to see the voluptuous young actress, cavorting in the fields of the Po Valley, clad in a tight sweater, shorts and thigh-high black stockings. She was flooded with offers from Hollywood and London but turned them all down to marry the film's producer, De Laurentiis, and work for his company. After her wedding she settled down to a quiet married life but was soon persuaded to return to movies. A year after the birth of a second daughter in 1952, she starred in "Ulysses" with Kirk Douglas and Anthony Quinn, and made her mark as a mature beauty in "The Gold of Naples" in 1954. She eventually starred in about 30 other movies, for such directors as Vittorio De Sica, Pasolini, Mario Monicelli and Luchino Visconti. Visconti gave her an almost wordless but memorable role as a stylish Polish mother in "Death in Venice." Although her fame was overshadowed by two other haunting beauties of the Italian screen, Sophia Loren and Gina Lollobrigida, she beat out the latter in auditions for "Bitter Rice." Miss Mangano shunned publicity and the trappings of fame and was reluctant to attend the usual rounds of news conferences and film festivals. When she did give interviews, she was reticent about her private life and spoke only of her roles as an actress. She never seemed comfortable in the role or even in making movies. "I agreed to appear in 'Bitter Rice' more because I needed money than out of the desire to have a film career," she once told an interviewer. The actress once said: "I never liked myself, neither when I was a roundish girl nor when I became a slender woman." After a long absence from the screen, she had a small role in the 1984 film, "Dune," and appeared in the 1986 film, "Dark Eyes," along with Marcello Mastroianni, whom she described as her first love. "We used to live in the same part of Rome when we were kids. We were in love; I was 16 and he was 22." As to her infrequent movie roles, she explained at the time: "The truth is that making films is not my passion, and I thought it was better for me not to work." She separated from De Laurentiis in 1983, and filed for divorce last year. The couple had three daughters, and a son who died in an air crash in Alaska in 1981. She spent the last few years living in Madrid with Francesca, her youngest daughter, who is married to a Spanish film producer.