BACKGROUND Epidemiological data on ethnicity and health in Sweden have mostly been derived from small populations and focused on morbidity. The present study highlights the relation between country of birth, adjusted for other social variables, and total mortality and mortality from circulatory diseases and coronary heart disease (CHD). METHODS The interviews with 21,420 males and 21,977 females aged 20-74 were conducted during a 7-year period, 1979-1985. The data consist of seven independent samples of the Swedish population. The present investigation was designed as a longitudinal follow-up study ranging from the day of the interview to 31 December 1993. Mortality data were obtained from the Cause of Death Register based on the Swedish national registration number. Person-years at risk were calculated from the date of the interview until death, or for those who survived, until the end of the follow-up period. The data were analysed by sex, using a proportional hazard model. RESULTS Men born in Finland had an increased mortality from all causes of death. Women born in Finland had an increased mortality risk for circulatory diseases with a relative risk (RR) of 2.15 (95% confidence interval [CI] : 1.45-3.20) when adjusted for age, marital status, form of housing tenure and years of education. The relationship between being a woman born in Finland or Eastern Europe and mortality for coronary heart disease (CHD) was significant with an RR of 2.18 (95% CI : 1.24-3.81) and 3.02 (95% CI : 1.24-7.34) respectively. The form of housing tenure was significantly associated with mortality in all models. Education showed a graded relation to total mortality and to mortality from circulatory diseases and CHD. CONCLUSIONS The increased mortality risk for Finnish males and females and, in addition the increased circulatory disease mortality risk for Finnish females and the strongly increased risk for CHD mortality for females born in Finland and Eastern Europe could not be explained by confounding by age, marital status or socioeconomic position.