Hepatitis B surface antigen and liver function tests were carried out to evaluate the degree of hepatic damage in 147 leprosy patients admitted in Sorok National Leprosarium. In 147 leprosy patients, 118 were of a lepromatous type, 16 were of a tuberculoid type and 13 were of a borderline group. The results were obtained as follows; 1. In leprosy patients, HBsAg positivity was observed in 4(2.7%) lepers, which was lower than 4(4%) positivity in normal control group. 2. The abnormal elevations of serum alkaline phosphatase, SGOT, SGPT and 777 were observed in 37(25.2%), 24(16.3%), 12(8.2%) and 20(13.5%) lepers respectively. Inverted A/G ratio was noticed in 28(19.0%) lepers. These data of various liver function tests except for SGPT tests in leprosy patients were statistically significant. 3. The abnormal elevations of serum alkaline phoshatase were chiefly observed in the lepers below age of 20 years, in borderline group and in the group of treatment with rifampin. The abnormal elevations of SGOT and inverted A/G ratio seemed to be increased with duration of illness and treatment.