We report the results of a prospective and randomized trial designed to study the incidence of abdominal and pulmonary complications in gallstone surgery comparing subcostal (SI) with midline incision. The need for postoperative analgesia was lower in the SI group. There was no difference in the degree of hypoxaemia in the first two postoperative days, but there was less impairment of pulmonary function in terms of vital capacity and forced expiratory volume in 1 s (P less than 0.0001) in the SI group. SI patients also had a lower incidence of pulmonary or abdominal complications but the difference was not significant. Finally, we found a reduced hospital stay for the SI patients (P less than 0.01), probably related to a reduced postoperative analgesic requirement and an improved pulmonary function. We conclude that subcostal incision is a better approach for biliary tract surgery and should be used whenever possible.