Between 1979 and 1987, 22 patients underwent resection for a benign liver tumor. A total of 24 tumors were resected: 8 adenomas, 8 focal nodular hyperplasias and 8 hemangiomas. In two patients, focal nodular hyperplasia was associated with hemangioma. Preoperative diagnosis of the nature of the tumor by radiologic investigations (ultrasonography, CT-scan, and selective angiography) was made in only 4 patients (18 p. 100), 3 with hemangioma and one with focal nodular hyperplasia. Ten patients underwent major hepatectomies and 12 had either a segmentectomy (8 patients) or atypical resection (4 patients). Progress in operative management significantly decreased transfusion of packed red cells (p less than 0.05) and that of fresh frozen plasma (p less than 0.02). Ten patients received no blood for fresh frozen plasma. Suppression of abdominal drainage when surgery was uneventful significantly decreased postoperative in-hospital stay (p less than 0.05) to a low 7.8 +/- 0.8 days and improved comfort of patients. These results confirm that preoperative diagnosis of a benign liver tumor is uneasy. They suggest that resection has become a benign procedure in selected surgical centers. The risk of ignoring malignant tumors or leaving a tumor with potential complications should prompt resection when the nature of a liver tumor has not been precisely determined by usual radiologic investigative procedures.