129 blood donors found to be HBsAg-positive on routine testing were studied for evidence of hepatic disease. Twelve had already lost the antigen from the serum when histologically examined. None of these has had clinical or histological evidence of inflammatory liver disease. Two of the 129 patients showed mild icteric hepatitis, cleared the antigen during the follow up and became anti-HBs positive. The remaining 115 patients who appeared clinically healthy and who had no history of previous icteric liver disease remained HBsAg positive during a mean follow up period of 17.3 +/- 3.0 months. Forty patients from these had a normal liver histology and 37 mild to distinct steatosis but no signs of inflammatory liver disease. 11 patients a mild nonspecific mesenchymal activity but no focal necrosis, 16 patients had mild infiltration in portal tracts and a few necrotic parenchymal cells with mesenchymal reaction, 6 patients had chronic persistent hepatitis, 4 chronic aggressive hepatitis, and 1 definite posthepatic cirrhosis.