OBJECTIVES: To calculate the cost-effectiveness of daily treatment of 160mg valsartan/25mg HCTZ for systemic arterial hypertension (SAH) as compared with 16mg candesartan/12.5mg HCTZ and with 80mg telmisartan/12.5mg HCTZ. METHODS: The information used in this model originates from a study comparing therapeutic effectiveness of valsartan/HCTZ in combination versus combinations of candarstan/HCTZ and of telmisartan/HCTZ for the treatment of SAH. Patients received 16mg candesartan/12.5mg HCTZ or 80mg telmisartan/12.5mg HCTZ daily for 4 weeks. The Mean Sitting Diastolic Blood Presure (MSDBP) was measured at the beginning and at the end of the 4-weeks treatment. Those patients who were not controlled using either of these regimens (MSDBP°Ý 90 mm Hg) were given daily doses of 160mg valsartan/25mg HCTZ for a further 4 weeks. RESULTS: Patients who received 16mg candesartan/12.5mg HCTZ or 80mg telmisartan/12.5mg HCTZ showed a 28% success rate in achieving a MSDBP<90 mm Hg. Patients who received 160mg valsartan/25mg HCTZ demonstrated a 74% success rate for the same parameter. Furthermore, the reduction in MSDBP in those patients who received 160mg valsartan/25mg HCTZ was 10.3 mm Hg greater than that obtained in the first phase of the study (p<0.0001). The only important difference in the use of medical resources related to these therapies was the cost of the medicines involved. The monthly anti-hypertensive treatment cost for the 160mg valsartan/25mg HCTZ combination was the lowest of the three combinations at $295.71 Mexican pesos (US$26.88) as compared with $354.54 Mexican pesos (US$32.23) for the 16mg candesartan/12.5mg HCTZ combination and $428.51 Mexican pesos (US$38.95) for 80mg telmisartan/12.5mg HCTZ. CONCLUSIONS: The combination of 160mg valsartan/25mg HCTZ is more effective and less expensive than either 16mg candesartan/12.5mg HCTZ or 80mg telmisartan/12.5mg HCTZ. According to these findings, treatment with 160mg valsartan/25mg HCTZ totally dominates and it should be preferable. Sensitivity analysis confirmed the results from this base case.