Nine-hundred-and-twenty-two hypertensive patients were included in a substudy to the Hypertension Optimal Treatment study, which aimed to investigate the impact on quality of life of lowering the pressure and of intensified therapy. Seven-hundred-and-eighty-one patients completed both baseline and follow-up questionnaires (intention-to-treat population), while 610 patients were included in a per protocol analysis. Patients were randomized to three diastolic BP levels (DBPs), i.e. < or =90 mmHg, < or =85 mmHg and < or =80 mmHg. Two self-administered validated questionnaires, the Psychological General Well-Being index and the Subjective Symptoms Assessment Profile (SSA-P) were completed at baseline and after 6 months. The lower the DBP achieved, the greater the improvement in well-being (p < 0.05). The increase in well-being from baseline to 6 months was significant in target groups < or =80 mmHg (p < 0.01) and < or =85 mmHg (p < 0.05). The SSA-P domains, cardiac symptoms and dizziness improved in all groups but the sex life score deteriorated in the < or =80 and < or =85 mmHg groups in male patients. In all target groups, headaches were reduced (p < 0.001), while swollen ankles (p < 0.001) and dry cough in the < or =80 mmHg group (p < 0.001) increased. Although more intensive antihypertensive therapy is associated with a slight increase in subjective symptoms, it is nonetheless still associated with improvements in patients' well-being.