Conventional treatment of Hirschsprung's disease consists of initial colostomy followed by pull-through (staged PT). During the past decade immediate definitive operation (primary PT) has been reported by several investigators with a complication rate ranging from 0% to 20%. In the authors' institution primary PT has been performed since 1992 in patients with rectosigmoid aganglionosis responsive to rectal irrigations. The authors reviewed the records of all patients (n = 124) with Hirschsprung's disease diagnosed and treated between 1989 and 1995. One hundred sixteen patients underwent a definitive operation. This study analysed the complications observed in 87 of these patients with aganglionosis limited to the rectosigmoid colon. Patients were divided into groups according to the type of surgical treatment (staged versus primary), the year of operation (1989 through 1992 versus 1992 through 1995), and the age at primary PT (15 infants age < or = 4 months versus 10 children age > 4 months). There were no deaths. There was no significant difference in complication rates between staged PT and primary PT. Similar complication rates were encountered in infants and children who underwent primary PT. The rate of postoperative complications did not change according to the year of the operation. Major complications were observed in all 3 patients who had a primary Swenson PT compared with 20% who had a primary Duhamel PT. Staged Swenson and Duhamel PT had similar complication rates. The authors conclude that (1) staged PT for rectosigmoid Hirschsprung's disease is not any safer than primary PT; (2) primary PT can be performed safely in young infants; and (3) primary Swenson PT is less satisfactory than primary Duhamel PT.