The Liver Cancer Study Group of Japan statistically analyzed 4658 cases of primary liver cancer diagnosed from January 1, 1980 to December 31, 1981 in over 400 hospitals throughout the country. The study group comprised 2038 cases of hepatocellular carcinoma, 146 of cholangiocarcinoma, 33 of mixed carcinoma, 30 of hepatoblastoma, six of sarcoma, and 33 others. In 2286 cases (49.1%) a histologic diagnosis was available. The survey, based mostly on the histologically proven cases, describes histologic features of the tumors, grade of anaplasia and growth patterns of the tumor cells, pathology in noncancerous portions of the liver, distant metastases, medical history, frequency of hepatitis in the 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.