Altman was born on May 7, 1939, in Montreal, Quebec, Canada. His parents, Ray (Arlin), a textile worker, and Victor Altman, a grocer, were immigrants to Canada, each coming from Eastern Europe as a young adult, in the 1920s. Altman's mother was from Białystok in Poland, and had come to Canada with her sister at the age of eighteen, learning English and working in a textile factory to earn money to bring the rest of their family to Quebec. Altman's father, born in Ukraine, had been a worker on a collective farm in the Soviet Union. He was sponsored to come to Canada as a farm worker, but later, as a husband and a father of two sons, he supported the family by running a small grocery store in Montreal. Sidney Altman was later to look back on his parents' lives as an illustration of the value of the work ethic: "It was from them I learned that hard work in stable surroundings could yield rewards, even if only in infinitesimally small increments."