The mortality of 95,647 persons, widowed during 1972-76 and identified by linking the Finnish Population Register and cause-of-death files, was followed up to the end of 1976. A total of 7,635 deaths during 225,251 person-years of experience were observed. Cause-specific standardized mortality ratios by time after bereavement were computed. The highest relative mortality risk was found immediately after bereavement. For all natural causes, mortality during the first week was over two-fold compared to expected rates. The relative risk was larger for ischemic heart disease (RR = 2.3 for men, and RR = 3.5 for women), an effect found in all age groups. Among men under age 65, excess mortality from IHD was also observed during later years of widowhood. For violent causes, exclusive of accidents simultaneously affecting both spouses, mortality was over two-fold during the first month. Mortality from suicides was greater than expected during the first years of widowhood. While the greatest excess mortality after bereavement seems to be due principally to the acute effects of becoming widowed, there also seems to be some excess mortality in younger persons widowed for a longer time.