The relation of leisure time and occupational physical activity to the risk of death from ischemic heart disease was investigated in a cohort of 15,088 persons aged 30-59 years who had no history of cardiovascular disease or other condition which hindered physical activity. Two population samples were randomly chosen from eastern Finland. During a six-year follow-up, persons who were sedentary in leisure time (relative risk = 1.3, 95% confidence interval (CI) = 1.1-1.6) or at work (relative risk = 1.3, 95% CI = 1.1-1.6) had an excess risk of ischemic heart disease death when adjusted for age, health status, family history, and body mass index in multivariate logistic models. Adjustment for years of education, social network participation, cigarette consumption, serum cholesterol level, and blood pressure level weakened the residual association of low leisure time physical activity with the risk of ischemic heart disease death (relative risk = 1.2, 95% CI = 1.0-1.5), whereas the association for low occupational physical activity remained unchanged. The lack of leisure time physical activity and a sedentary occupation are associated with an increased risk of ischemic heart disease death, and the excess risk due to lack of leisure time physical activity is, in part, accounted for by other ischemic heart disease risk factors.