OBJECTIVES: To estimate the impact of the of vildagliptin  reimbursement within the limits of type 2 diabetes mellitus treatment on the budget of the National Health Fund in Poland. METHODS: The budget impact analysis was performed with two years time horizon, from the public payer’s perspective (National Health Fund) and also from both payers’ perspective (National Health Fund and the patient). Polish cost data was used (only oral anti-hyperglycemic drugs were considered). Two scenarios were compared: present - without reimbursement of vildagliptin, and future - after reimbursement of vildagliptin. The prognosis of market vildagliptin shares, sent by the Novartis Poland, was used in the analysis. The rate of other oral anti-hyperglycemic drugs was estimated on the base of IMS data about the number of units sold in the first three quarters of the year 2008. Sensitivity analysis was performed to test the impact of changes in the assumed parameters of the analysis. RESULTS: Assuming the reimbursement of vildagliptin annual expenses from the budget of National Health Fund for anti-hyperglycemic drugs would raise by 320.4 thousand PLN (72 thousand €)  in 2009 and 612.3 thousand PLN (137.7 thousand € ) in 2010. Annual expenses from the budget of both payers would raise by 579.5 thousand PLN (130.3 thousand €) in 2009 and 1.2 mln PLN (261 thousand €) in 2010. Depending on parameter changes, the budget would change by ±17% and ±19% for NHS and both payers perspective, respectively. CONCLUSIONS: The reimbursement of vildagliptin will cause the raise of NHF expenses by 0.37% in 2009 and 0.70% in 2010 of the budget spent for oral drugs reimbursed in diabetes mellitus. For both payers’ perspective, the reimbursement of vildagliptin will cause the raise expenses by 0.27% in 2009 and 0.53% in 2010 of the budget.