The aim of this study was to carry out an analysis of the cost effectiveness of antihypertensive drug treatment in different patient groups in Sweden. The cost-effectiveness ratios were estimated as net costs (treatment costs minus reduced costs of cardiovascular morbidity) divided by the number of life-years gained (the increase in life expectancy). The analysis was based on the reduction of coronary heart disease and stroke in the most recent meta-analysis of antihypertensive treatment, to which Swedish cost data were applied. We found that the cost per life-year gained decreases with age for both men and women, and is relatively low for middle-aged and older patients, even when the diastolic blood pressure (DBP) range is 90 to 94mm Hg. In conclusion, the results indicate that, in Sweden, antihypertensive treatment is generally cost effective in middle-aged and older patients with a DBP of > or = 90 mm Hg. However, it is questionable whether it is generally cost effective to treat younger patients with mild hypertension.