Sera were tested for autoantibodies in 98 patients with cryptogenic cirrhosis in Uganda and results correlated with serological tests for hepatitis B surface antigen (HBs Ag) and antibody to HBs Ag (HBs Ab). Smooth muscle antibodies (SMA) were detected in 23 (24%) of the patients but there was no difference in the incidence of SMA between HBs Ag-positive and negative cases. Antinuclear antibodies (ANA) were detected in five cases; mitochondrial, gastric and thyroid antibodies were not found in any patient. Unlike other geographical locations autoimmune mechanisms appear to play little part in the progression of chronic liver disease in Uganda Africans. Hepatitis B surface antigen was present in 36 (37%) and HBs Ab in 47 (48%) of the patients. Although evidence for past exposure to hepatitis B virus (as shown by detection of HBs Ab) was present in at least 30 out of the 62 HBs Ag-negative cases, there was no greater incidence of autoantibodies in HBs Ag-negative patients with or without HBs Ab. Persistent infection with hepatitis B virus and continuing liver damage may be an important factor but these results do not favor a role for the virus in causing chronic liver disease by triggering off an autoimmune reaction.