OBJECTIVES: LIFE was a double-masked, randomized trial of losartan vs. atenolol in 9193 patients with essential hypertension and LVH ascertained by electrocardiography. Losartan reduced the primary composite endpoint of cardiovascular death, myocardial infarction, or stroke by 13% (p=0.021) and reduced the risk of stroke by 25% (p=0.001), despite a similar degree of blood pressure control. Our objective was to assess the cost-effectiveness of losartan compared with atenolol in hypertensive patients with LVH, from the perspective of the Spanish healthcare system. METHODS: Losartan and atenolol utilisation within the trial period and lifetime direct medical costs following a stroke in Spain were combined with estimates of reduction in life expectancy following stroke. The cumulative incidence of stroke and study medication utilization after 5.5 years of patient follow-up were separately estimated, adjusting for baseline degree of LVH and Framingham risk score. To estimate per patient lifetime stroke costs, we multiplied the cumulative incidence of stroke by the lifetime direct medical cost attributable to stroke. All costs and benefits are in 2004 Spanish prices discounted at 3% annually. RESULTS: Losartan reduced stroke-related cost by 270€ per patient due to a lower cumulative incidence of stroke at 5.5 years (4.9% vs. 6.5%; p=0.003). Net costs were 1626€ higher per patient over 5.5 years for losartan compared with atenolol. The number of life-years gained (LYG) by preventing a stroke was 5.6 years, resulting in 0.090 (discounted) LYG per patient with losartan. The estimated cost per LYG for losartan was 18,147€ (95% CI: 10,127, 46,724) which is well within bench-mark values (30,000€/LYG) for accepted cost effective interventions in Spain. The probability of the cost-effectiveness ratio falling below a threshold of 30,000€/LYG was 0.88. CONCLUSIONS: Treatment with losartan compared with atenolol over a 5.5 year period is, based on the cost per LYG, a cost-effective intervention in Spain.