OBJECTIVE--To examine the association between self reported alcohol intake and subsequent mortality from all causes and if the effect of alcohol intake on the risk of death is modified by sex, age, body mass index, and smoking. DESIGN--Prospective population study with baseline assessment of alcohol and tobacco consumption and body mass index, and 10-12 years' follow up of mortality. SETTING--Copenhagen city heart study, Denmark. SUBJECTS--7234 women and 6051 men aged 30-79 years. MAIN OUTCOME MEASURE--Number and time of deaths from 1976 to 1988. RESULTS--A total of 2229 people died, 1398 being men. A U shaped curve described the relation between alcohol intake and mortality. The lowest risk was observed at one to six alcoholic beverages a week (relative risk set at 1). Abstainers had a relative risk of 1.37 (95% confidence interval 1.20 to 1.56) whereas those drinking more than 70 beverages a week had a relative risk of 2.29 (1.75 to 3.00). Among the drinkers, the risk was significantly increased only among those drinking more than 42 beverages a week. Sex, age, body mass index, and smoking did not significantly modify the risk function. The risk among heavy drinkers was slightly reduced when smoking was controlled for. The risk function was similar in the first and second period of six years of observation. CONCLUSION--Alcohol intake showed a U shaped relation to mortality with the nadir at one to six beverages a week. The risk function was not modified by sex, age, body mass index, or smoking and remained stable over 12 years.