OBJECTIVE: To project the life expectancy (LE) and costs of treating patients with diabetes, hypertension, and microalbuminuria with irbesartan 300mg. METHODS: A long-term Markov model simulated progression from microalbuminuria to nephropathy, doubling of serum creatinine, end-stage renal disease (ESRD), and all-cause mortality in patients with hypertension, type 2 diabetes and microalbuminuria. Three strategies were compared: early use of irbesartan (begun in subjects with microalbuminuria), late use of irbesartan (begun only in subjects with nephropathy), and standard hypertension care (with comparable blood pressure control). The model was based on data from the Irbesartan in Reduction of Microalbuminuria-II study and the Irbesartan and Diabetic Nephropathy Trial. Both studies demonstrated significant reductions in the progression of diabetic renal disease. ESRD-related costs and outcomes were retrieved from the French-specific published or official sources. Cost savings and life years saved were projected for a hypothetical cohort of 1000 subjects with baseline age 58 years. Future costs and LE were discounted at 3% yearly. A 25-year time horizon and third party payer perspective were used. Extensive sensitivity analyses were performed. RESULTS: When compared to standard care, early use of irbesartan in 1000 subjects was projected to save €25.7 million (95%CI 16.8-32.3), while late use of irbesartan was projected to save €9.2 (3.4-14.1) million. Similarly, early use of irbesartan was estimated to add 796 (520-1050) life years, while late use of irbesartan added 60 (22-92) life years. The superiority of early use of irbesartan over late use and standard care was robust under a wide range of plausible assumptions. CONCLUSIONS: Treating patients with hypertension, microalbuminuria and type 2 diabetes with irbesartan was projected to extend life and reduce costs. Late use of irbesartan (when overt nephropathy develops) is also better and less costly than standard care, but irbesartan should be started earlier and continued long-term.