The purpose of this study was to define the optimal international normalized ratio (INR) intensity of oral anticoagulant therapy in Chinese patients with valve replacement surgery. We studied 1,658 patients who underwent mechanical valve replacement in Beijing Anzhen Hospital; the focus of the study was on correlation between intensity of anticoagulant therapy and thromboembolism/hemorrhage complications. We further followed up 1,508 patients for 46 +/- A 16 months (range 1-61 months). Average INR was 2.13 +/- A 0.56, and warfarin dose was 3.09 +/- A 0.85 mg/day. The incidence rate of anticoagulation-related thromboembolism was 1.17 per 100 patient-years (%/pt-y), and the incidence rate of anticoagulation-related hemorrhage was 2.02%/pt-y. The incidence rate of total complications (i.e., combined thromboembolism and hemorrhages) was 3.24%/pt-y. The rate of total complications in group on INR 1.3-2.3 (aortic valve replacement: 1.3-1.8; mitral valve replacement and double valve replacement: 1.8-2.3) was the lowest among all anticoagulant therapy regimens followed. In conclusion, the relatively low anticoagulant strategy presented above efficiently prevents thrombosis and hemorrhage complications.