OBJECTIVE: To evaluate the cost-saving of pharmacist intervention on warfarin therapy in Thai patients with mechanical heart valves from provider perspective. METHODS: Decision tree model was used to estimate the cost saving of pharmacist intervention on warfarin therapy. Only direct cost was used in the simulations. Estimates were based on the studyevaluating the impact of education and counseling by clinical pharmacists on anticoagulation therapy in patients with mechanical heart valves of Siriraj Hospital cost data were obtained from Siriraj Hospital. RESULTS: The mode estimates that pharmacist intervention can save cost on warfarin therapy in Thai patients with mechanical heart valves 12,049.89 baht ( $301.25 ) per patient per year (3,313,172.43 baht ( $82829.31 ) for total per year) CONCLUSIONS: Pharmacist intervention can provide substantial saving and present a favorable economic profile in the treatment of warfarin therapy in Thai patients with mechanical heart valves