In a retrospective study over a 20-year period we found in the Umeå region in Sweden 11 patients (7 women and 4 men, mean age 67 years) with both hepatocellular carcinoma and acute intermittent porphyria. This coincidence was highly significant. Concomitant existence of portal cirrhosis of the liver was demonstrated in those 5 patients in whom it could be examined.