The authors investigated the frequency of alpha-fetoprotein(AFP) and hepatitis B surface antigen(HBsAg) in 135 cases of the primary hepatocellular carcinoma, clinically and pathologically diagnosed in Busan National University Hospital and affiliated hospitals in Busan during a period of 28 months from June 1976 to September 1978. Serum AFP was detected by Ouchterlony microimmunodiffusion method and serum HBsAg was detected by counterimmuno-electrophoresis. The results obtained were as follow: 1. Serum AFP was detected in 81(60%) out of 135 cases of primary hepatocellular carcinoma but were not detected in all cases out of 331 of healthy person and 108 of other liver diseases. 2. Serum HBsAg was detected in 16(11.9%) out of 135 cases of primary hepatocellular carcinoma and in 15(4.5%) out of 351 cases of healthy control. The HBsAg postive rate of the primary hepatocellular carcinoma was significantly higher than that of the healthy control. 3. The serum HBsAg positive rates between the AFP positive and negative hepatocellular carcinoma was not significantly different. 4. No influence of sex and age was found between AFP positive and negative hepatocellular carcinoma and between HBsAg positive and negative hepatocellular carcinoma between HBsAg positive and negative hepatobellular carcinoma. On the basis mentioned above, it is suggested that there is no correlation between serum AFP and HBsAg in primary hepatocellular carcinoma.