Effectiveness of antihypertensive treatment depends not only on drugs that avoid or minimize symptomatic side effects but also on therapy that has a positive effect on quality of life. This study assessed the effect on quality of life of a contemporary agent (an angiotensin receptor blocker) and evaluated the validity and practicality of using a quality-of-life instrument in the practice-based setting. A total of 2716 hypertensive patients, either untreated or on single-agent therapy, were started on or switched to 40 mg telmisartan for 6 weeks; in patients whose blood pressures remained above 130/85 mm Hg after 2 weeks, the dose was increased to 80 mg for the remaining 4 weeks of treatment. Quality of life was measured by patient self-administration of the Psychological General Well-Being Index (GWBI) at baseline and at the end of the study. Sixty-eight percent (n=1858) of patients treated with telmisartan fully completed both GWBI tests; the test score increased by 5.2+/-0.3 (p<0.0001) from 77.7+/-0.4. This improvement was observed across all six emotional and health subscales of the GWBI. White and black patients, those aged <65 or >/=65 years, and men and women had similar increases, though the baseline value in women was sharply lower (p<0.001) than in men. The GWBI rose more in patients whose blood pressure was controlled by treatment (<140/90 mm Hg) than in noncontrolled patients (6.1 vs. 4.1, p<0.0001); for all patients the decreases in systolic and diastolic blood pressures produced by telmisartan correlated significantly (p<0.001 for each) with the increases in the GWBI scores. Controlling blood pressure appears to be an important element in improving subjective health perceptions of hypertensive patients.