ABSTRACT— In a survey of the etiology of hepatic steatosis, none of the known causes of fatty liver was identified in 12 of 137 patients with severe fatty changes (more than 50% of hepatic cells containing fat vacuoles) diagnosed over a 4-year period. The retrospective analysis of the clinical records of these patients disclosed the absence of symptoms, liver biopsy being performed because of persistent hypertransaminasemia, which had been discovered fortuitously in 10 cases and after acute hepatitis in two. None had HBsAg in serum. In addition to fatty changes, lobular necrosis was found in 11 cases and chronic inflammation of portal tracts in eight. Patients remained asymptomatic and had raised transaminases during a follow-up ranging from 1 to 3 years. The clinical, biochemical and follow-up features of these patients closely resemble those of patients with chronic hepatitis in Mediterranean countries. Thus it can be suggested that in some cases fatty liver may be a prominent feature of chronic hepatitis.