An increasing number of elderly patients require mitral valve surgery (MVS), but due to a perceived increase in risk of morbidity and mortality following cardiac surgery, many such patients are not referred for treatment. The outcome of MVS in elderly patients in terms of hospital morbidity and mortality, ICU and hospital stays, change in NYHA class and quality of life was assessed in 43 elderly patients (18 males, 25 females; median age 77 years) who underwent primary mitral valve repair (MVRr) or replacement (MVR) between November 1994 and September 1997. Preoperative clinical characteristics, hospital morbidity and mortality, and ICU and hospital stays after MVS were recorded. At surgery, 69% of patients were in NYHA class III/IV, 36% underwent non-elective surgery and 44% had symptoms of more than three years' duration; 80% of patients presented with mitral incompetence and 51% had MVRr. Median bypass and cross-clamp times for MVRr were significantly longer than for MVR. After surgery, 98% of patients required inotropic support, 9% renal dialysis, and 42% ventilatory support for >24 h. In addition, 37% developed respiratory complications, 12% renal failure, 19% needed re-exploration for bleeding, and 5% suffered a stroke. The mean ICU stay after MVS was three days; average hospital stay was 10 days. The 30-day mortality rate was 22.7% after MVRr and 38% after MVR. There was a significant improvement in energy, and role limitation due to physical and mental health after MVS. In conclusion, elderly patients underwent MVS, usually after a degree of clinical deterioration. Morbidity and mortality after MVS were high, but a significant improvement was seen in both symptoms and quality of life of survivors.