Management of anticoagulant therapy after mechanical valve replacement is difficult in developing countries because of patient non-adherence. The effect of depression on adherence to drug therapy and to a clinic visit schedule was evaluated for 62 patients who received prostheses. All were prescribed a once-per-day regimen of warfarin and were scheduled for three appointments at the anticoagulant clinic for dose adjustment at 3-week intervals. According to the Center for Epidemiological Studies Depression Scale, 22 were depressed. Non-depressed patients were more compliant than depressed patients; adherence was inversely correlated with depression scores. While depression had no relationship with age, sex and cardiac symptoms, there was a relationship with anxiety and poor social support