OBJECTIVES: To obtain the incremental cost for avoiding a transition from a diagnosed IGT to diabetes through a treatment based in the use of the Acarbose drug compared to the normal practice. METHODS: Modelisation of the health and economic consequences (direct costs for the health system), in a period of 40 months, of implementing Acarbose or a non-drug treatment to a population of 1000 subjects diagnosed of IGT. The efficacy, adverse events, and the follow up of the pharmacological treatment data were obtained from a controlled clinical trial: STOP-NIDDM. The resources' cost data were obtained from published studies focused on the Spanish Health System. The differential resources' use of both treatments (visits, tests, etc.) was actually discussed with an expert in diabetes. RESULTS: The incremental cost of avoiding the transition to type 2 DM from a IGT state with the pharmacological treatment based on the use of Acarbose is about €3386, and the incremental cost per year of diabetes avoided is about €1736. Additionally the evaluated treatment has significant results reducing cardiovascular events. CONCLUSION: In order to evaluate all the positive effects of the treatment, a longer-term cost-benefit analysis and a comparison of the pharmacological treatment of Acarbose with other 2 DM prevention alternatives (basically the ones related to the life style) would be needed.