Thirty patients undergoing bilateral breast reduction by inferior pedicle technique were entered into a prospective, randomized study to determine the effect of unilateral saline wound irrigation and body mass index (BMI) on outcome. Each patient was assessed at 1, 4, and 8 weeks after surgery for wound dehiscence, infection, fat necrosis, and breast comfort by means of a visual analog pain score. The mean patient age was 33 years; mean weight, 67.7 kg; mean BMI, 26.3; and mean weight of breast tissue excised per patient, 1270 g. In 60 breasts there were 13 cases of minor wound breakdown, all of which had healed by 8 weeks postoperatively. Wound irrigation had no significant effect on the rate of T-junction breakdown or on postoperative pain. BMI was associated significantly with wound breakdown (BMI > 26.3, 33% wound breakdown rate; BMI < 26.3, 10% wound breakdown rate; P < 0.05, χ2 test). Patients with a high BMI are more likely to have delayed healing after breast reduction.