Background: Bariatric surgery ameliorates obesity-associated diseases, resulting in psychological and social benefits. Long-term studies of its effects on quality of life (QOL) assessed with well established instruments are lacking. This prospective study investigated the long-term effects of gastric banding on health-related QOL using an obesity-specific validated measure. Methods. The Health Related Quality of Life (HRQL) questionnaire was completed by 50 severely obese patients before surgery and at 1, 2.5 and 5 years after gastric banding. Ninety-eight subjects with normal weight, matched for age, sex and education, also completed the HRQL questionnaire as controls. Results: Surgery was successful in all patients. Mean excess weight loss after 1, 2.5 and 5 years was 42.1, 42.2 and 41.6 per cent respectively. General wellbeing, health distress, depression, perceived attractiveness and self-worth improved significantly over the 5 years and, except for general wellbeing, were still improving after 5 years. There were increases in physical activity and work productivity. Successful weight loss was the main determinant of general wellbeing and health distress, and these were adversely affected by band-related complications. In subjects with a body mass index below 30 kg/m(2), scores improved to values for subjects of normal weight. Conclusion: Bariatric surgery resulted in sustained improvement in health-related QOL even though not all excess weight was lost. Normalization of health-related QOL may necessitate greater weight losses.