The population of Leningrad suffered from severe starvation, cold and psychological stress during the siege in World War II in 1941–1944. We investigated the long-term effects of the siege on cancer mortality in 3,901 men and 1,429 women, born between 1910 and 1940. All study subjects were residents of St. Petersburg, formerly Leningrad, between 1975 and 1982. One third of them had experienced the siege as children, adolescents or young adults (age range, 1–31 years at the peak of starvation in 1941–1942). Associations of siege exposure with risk of death from cancer were studied using a multivariable Cox regression, stratified by gender and period of birth, adjusted for age, smoking, alcohol and social characteristics, from 1975 to 1977 (men) and 1980 to 1982, respectively (women), until the end of 2005. Women who were 10–18 years old at the peak of starvation were taller as adults (age-adjusted difference, 1.7 cm; 95% CI, 0.5–3.0) and had a higher risk of dying from breast cancer compared with unexposed women born during the same period (age-adjusted HR, 9.9; 95% CI, 1.1–86.5). Mortality from prostate cancer was nonsignificantly higher in exposed men. The experience of severe starvation and stress during childhood and adolescence may have long-term effects on cancer in surviving men and women. © 2008 Wiley-Liss, Inc.