The loss of health-related quality of life (QoL) associated with symptomatic breast hypertrophy has been well documented. Measuring QoL with a generic, single index, instrument enables comparisons between different diseases, conditions, and specialities. The aim of this study was to measure the health-related QoL of patients before and after reduction mammaplasty, and to compare it to that of the age-standardised female population, and patients treated by total joint replacement. Health-related QoL was measured using the 15D score from 82 patients at baseline, and at six months after breast reduction surgery from 29 patients who had been randomised to the procedure. At baseline those who had had reduction mammaplasty had significantly lower health-related QoL than the age-standardised female population, but by six months it had improved to the same level with population. The preoperative health deficit of symptomatic breast hypertrophy was equal to that of symptomatic major joint arthrosis. The effect of intervention of reduction mammaplasty was comparable to that of hip and more than knee total joint replacement.