OBJECTIVES: A Pharmacist-Managed Warfarin Service (PMWS) is perceived as an efficient method for improving anticoagulation control and decreasing the rate of bleeding, thus reducing overall healthcare costs. What this study aims to assess is a five-year budget impact of providing PMWS instead of Usual Medical Care (UMC) to patients on warfarin at the secondary/tertiary level of healthcare facilities in Serbia. METHODS: A budget impact analysis was performed from the payer’s perspective (National Health Insurance Fund-NHIF), over a five-year time horizon. A reference scenario (UMC) and a new one (PMWS) were defined for a cohort of 18,067 insured patients taking warfarin, with the pre-assumed annual population growth rate of 20%, according to NHIF database. Direct medical costs included the acquisition costs of warfarin, blood products and drugs for anticoagulation reversal, as well as hospitalization and monitoring. The expected values of annual therapy were based on the probabilities of patient being well-controlled or hypercoagulated, without any symptoms or with minor/major bleeding (pre-assumed incidence of the adverse events was once in a year, during 10 days). RESULTS: The projected net cost savings have amounted to €