Miguel Piñero began his first play in prison and went on to be acclaimed as a major new voice in the theater.  He died of cirrhosis of the liver at the age of 41 years old.

Mr. Piñero, who was born in Puerto Rico and grew up on the Lower East Side, started to write for the theater while serving time at the Ossining Correctional Facility (Sing Sing) for armed robbery. The result was ''Short Eyes,'' a searing portrayal of violent prison life, which started at the Theater of the Riverside Church, was transferred to the Public Theater by Joseph Papp, and then ran at the Vivian Beaumont Theater in Lincoln Center. ''Short Eyes,'' which won an Obie Award and the New York Drama Critics Circle Award as best American play in 1974, was later made into a film with a screenplay by Mr. Piñero under the direction of Robert Young.

''Miguel Piñero was the first Puerto Rican to really break through and be accepted as a major writer for the stage,'' Mr. Papp said.   ''He was an extraordinarily original talent, and he became a mentor and a hero for people like Reinaldo Povod, who wrote 'Cuba and His Teddy Bear.' The fact that Miguel was successful made it possible for Ray to write. All over the Lower East Side, Miguel was considered someone who had broken through. But in addition to being a symbol, he was a first-class playwright.''

Mr. Piñero's other works for the theater included ''Straight From the Ghetto,'' ''Eulogy for a Small-Time Thief,'' ''The Sun Always Shines for the Cool'' and ''A Midnight Moon at the Greasy Spoon.'' His Art Imitated His Life

His themes revolved around life on the mean streets he knew best, populated by drug addicts and con men, pimps and prostitutes. Drugs and crime were a persistent theme as well in Mr. Piñero's own life; he was arrested several times on drug and robbery charges.

Mr. Piñero, who also began performing while in prison, played the role of a Spanish-speaking drug dealer in the film ''Fort Apache, the Bronx,'' and appeared in ''Breathless,'' ''Alphabet City,'' ''Exposed,'' ''Deal of the Century,'' ''Times Square,'' ''Streets of L.A.'' and ''Pick-Up Artist,'' among other movies. His television appearances included roles in ''Baretta,'' ''Kojak'' and ''Miami Vice.'' A published poet, Mr. Piñero was one of the founders of the so-called Nuyorican movement, a group of Puerto Rican New York poets, and he edited an anthology of their work called ''Nuyorican Poetry.'' At the time of his death, he was working on a play for the Public Theater called ''Every Form of Refuge Has Its Price,'' which was set in the intensive-care unit of a hospital.