We experienced two patients with a prosthetic heart valve, who underwent hepatic resection for hepatoma while on anticoagulation therapy. Patients with a prosthetic heart valve have the following characteristics; an increased risk of thromboembolism due to diminished anticoagulation in the perioperative period, a greater risk of endocarditis due to the artificial material in the heart, and impaired cardiopulmonary function including possible arrhythmia and heart failure. Furthermore, when such patients also have liver cirrhosis with a hepatoma, there is an increased risk of perioperative bleeding while on anticoagulation due to coagulopathy and also a risk of infection due to decreased cellular immunity. Patients with a prosthetic heart valve therefore require special care and attention whenever they have to undergo hepatic resection. With respect to anticoagulation, a minimal level is required to prevent bleeding and thromboembolism. Warfarin being administered preoperatively may be switched to heparin while closely monitoring the activated clotting time (biomaterial valve: 130-150 sec, non-biomaterial valve: 150-180 sec); the heparin should then be changed back to warfarin immediately after starting oral intake following operation. For the prevention of infection, a broad spectrum antibiotic should be used prophylactically both intra-operatively and postoperatively. The cardiopulmonary function must also be carefully monitored. For the assessment of postoperative liver function, lecithin: cholesterol acyltransferase, serum bilirubin and albumin are useful because there is no relevance of coagulation parameters such as prothrombin time under anticoagulation.