We analyzed survival and causes of death among 163 patients with primary hemochromatosis diagnosed between 1959 and 1983. The mean follow-up period was 10.5 +/- 5.6 years (+/- S.D.). Cumulative survival was 92 per cent at 5 years, 76 per cent at 10 years, 59 per cent at 15 years, and 49 per cent at 20 years. Life expectancy was reduced in patients with cirrhosis of the liver as compared with those without cirrhosis (P less than or equal to 0.05), in patients with diabetes mellitus as compared with those without diabetes (P less than or equal to 0.002), and in patients who could not be depleted of iron during the first 18 months of venesection therapy as compared with those who could be depleted (P less than or equal to 0.001). Prognosis was not influenced by sex (P less than or equal to 0.5). Patients without cirrhosis had a life expectancy that was not different from that expected in an age- and sex-matched normal population. Analysis of the causes of death in 53 patients, as compared with the normal population, showed that liver cancer was 219 times more frequent among the patients (16 patients), cardiomyopathy was 306 times more frequent (3 patients), liver cirrhosis was 13 times more frequent (10 patients), and diabetes mellitus was 7 times more frequent (3 patients). Death rates for other causes, including extrahepatic carcinomas (seven patients), were not different from the rates expected. We conclude that patients with hemochromatosis diagnosed in the precirrhotic stage and treated by venesection have a normal life expectancy, whereas cirrhotic patients have a shortened life expectancy and a high risk of liver cancer even when complete iron depletion has been achieved.