Primo Levi, whose autobiographical writings drew on his experiences as an Auschwitz survivor and his training as a chemist, died today in Turin. He was 67 years old. The authorities said they were treating the death as a suicide. Mr. Levi was found by members of his family and neighbors at the foot of a stairwell in the home where he was born, in the Crocetta neighborhood, and he was pronounced dead on arrival at a hospital. Renzo Levi, the writer's son, said by telephone from Turin that his father had had serious bouts of depression in recent months. The elder Mr. Levi had undergone minor surgery recently, and friends suggested he was deeply troubled about the condition of his 92-year-old mother, who was partially paralyzed by a stroke last year. Already well known in Europe, Mr. Levi became prominent among American readers with the appearance in 1984 of the third volume of his autobiographical reflections, ''The Periodic Table,'' in which he used the chemical elements as a bridge to weave an unusual account of his experiences in the Nazi death camps. His other books include ''Survival in Auschwitz,'' the first volume of his autobiographical trilogy; ''The Reawakening,'' the second volume; ''Moments of Reprieve,'' a series of sketches of the author's acquaintances from the camps, and, most recently, ''The Damned and the Saved.'' He also wrote works of fiction, some of it under the pseudonym Damiano Malabaila. Primo Levi was born in Turin on July 31, 1919, a descendant of Jews who had settled in the Piedmont, in northern Italy, after the expulsion of Jews from Spain. He studied chemistry at the University of Turin, even after the Mussolini regime barred Jews from institutes of higher learning in 1938, and received a degree in 1941. In 1943, he quit his job at a Milan pharmaceutical laboratory to join Italian Partisans fighting German and Italian Fascist forces. ''I was not a very good Partisan,'' Mr. Levi told Herbert Mitgang in The New York Times in 1985. ''When my unit was betrayed by an informer, I was interrogated by Italian Fascists and handed over to the Germans. I was put on a train with hundreds of other Jews and sent to Monowitz-Auschwitz, the factory part of the camp that used slave labor.'' It was his experiences there, as No. 174517 - the number was tattooed on his left arm, a few inches above the wrist - that were to shape his life and work. His 1947 account, ''Survival in Auschwitz'' - also published under the title ''If This Is a Man'' - described daily life in the death camps in rich detail, creating a monument to the triumph of lucid intelligence over Nazi barbarism. He attributed his survival in the camp to luck, to the Germans' need for chemists - he was given a job in a synthetic-rubber factory - and to an acquaintanceship with a fellow inmate, an Italian bricklayer who was not Jewish, who brought him bread and soup. In ''The Reawakening,'' published in 1963, the author described his long and bizarre journey home to Turin after being liberated from the camp by Soviet soldiers. He also drew on his Partisan days in a novel, ''If Not Now, When?'' The novel, published in Italy in 1982, chronicled the exploits in the closing months of the war of a band of Eastern European Jewish Partisans who dream of finding freedom in Palestine. In recent years, Mr. Levi turned increasingly to works of fiction, including novels and short stories, and was a regular contributor of poetry to the Turin newspaper La Stampa. He was the winner of several literary prizes, including the Strega Prize, a prestigious Italian award, in 1979. In 1985 he and Saul Bellow shared the Kenneth B. Smilen fiction award, sponsored by the Jewish Museum in New York. While devoted to his writing, Mr. Levi continued his career as a chemist, working for a Turin paint factory, SIVA, for almost 30 years. From 1961 to 1974, he was the plant's general manager. In an interview with The New York Times in December 1984, Mr. Levi described himself as ''a chemist by conviction,'' but added, ''After Auschwitz, I had an absolute need to write.'' ''Not only as a moral duty,'' he said, ''but as a psychological need.'' That need was reflected in a Yiddish proverb he used as an epigraph for ''The Periodic Table'': ''Troubles overcome are good to tell.'' Mr. Levi wrote in an Italian enriched by snatches of the disappearing jargon of the Piedmontese Jews, which combined Hebrew roots with local endings and inflections. Mr. Levi, who came from a middle-class family of assimilated Jews, once wrote that ''a Jew is someone who at Christmas does not have a tree, who shouldn't eat salami but does, who has learned a little bit of Hebrew at 13 and then forgotten it.'' But he remained close to the Italian Jewish community and two years ago he contributed an introduction to the catalogue of a newly opened Jewish museum in Turin. The novelist Philip Roth, whose account of a conversation with the Italian appeared last October in The New York Times Book Review, said of Mr. Levi today: ''With the moral stamina and intellectual poise of a 20th-century titan, this slightly built, dutiful, unassuming chemist set out systematically to remember the German hell on earth, steadfastly to think it through, and then to render it comprehensible in lucid, unpretentious prose. He was profoundly in touch with the minutest workings of the most endearing human events and with the most contemptible.'' Mr. Roth called Mr. Levi ''a magically endearing man, the most delicately forceful enchanter I've ever known.'' Mr. Levi is survived by his wife, Lucia; a daughter, Lisa, and a son, Renzo.