From 1984 through 1994, 99 consecutive patients with hepatocellular carcinoma (HCC) underwent hepa-tectomy with microwave tissue coagulation (MTC). We performed limited resection (Hr0) in 28 patients, subsegmentectomy (HrS) in 25 patients, segmentectomy (Hr1) in 21 patients, and lobectomy or extended lobectomy (Hr2) in 25 patients. The patients were divided into two groups: group A, 86 patients with tumors smaller than 1 kg and no tumor thrombi in the main portal trunk; and group B, 13 patients with a tumor 1 kg or larger, or with macroscopic tumor thrombi in the main portal trunk. In group A, mean blood loss was 838 ml for Hr0, 1948 ml for HrS, 1765 ml for Hr1, and 1325 ml for Hr2. The mean operative time in group A ranged from 3 h 43 min for Hr0 to 4 h 57 min for Hr2. In group B, the mean operative time was 6 h 3 min and mean blood loss was 6053 ml. Our MTC method was associated with an in-hospital mortality rate of 3% and a major complication rate of 13.1%. The 5-year survival and disease-free survival rates were 43.4% and 25.4%, respectively. The 5-year survival rate of patients without portal tumor thrombi (50.9%) was significantly better than that of patients with portal tumor thrombi (11.9%) (P < 0.001). The 5-year survival rate of patients who underwent curative resection (58.1%) was significantly better than that of patients who underwent noncurative resection (22.9%) (P < 0.001). The 5-year survival rates of patients in group A without portal tumor thrombi did not differ between those who had cancer-negative margins (54.0%) and those with cancerpositive margins (49.6%) at resection. Recurrence and local recurrence rates did not differ in patients with cancer-positive margins (63.6% and 7.3%, respectively) and patients with cancer-negative margins (56.5% and 8.7%, respectively). These results suggested that microscopic residual cancer in the resected margin was coagulated by MTC. Blood loss, operative time, and clinical outcome in this series of 99 consecutive hepatectomies were comparable with values in earlier reports in which such hemostatic methods as the Pringle maneuver were used. We conclude that hepatectomy with MTC is useful and safe and produces consistent results.