The Liver Cancer Study Group of Japan statistically analyzed 2396 cases of primary liver cancer diagnosed from January 1, 1978 to December 31, 1979 in over 500 hospitals throughout the country. They comprised 1047 cases of hepatocellular carcinoma, 93 of cholangiocarcinoma, 9 of mixed carcinoma, 16 of hepatoblastoma, and 33 others. In 1198 cases (50%) a histologic diagnosis was available. The survey and analysis, based mostly on the histologically proven cases, describe the gross anatomic and histologic features of the tumors, grade of anaplasia and growth patterns of the tumor cells, pathology in noncancerous portions of the liver, distant metastases, past medical history, frequency of hepatitis in the past history, frequency of positive HBsAg and anti-HBs, age distribution, subjective symptoms, radiographic features (angiogram, scintiscan, computed tomography), ultrasonography, surgical procedures, extent of hepatic resection, and survival.