The incidence and outcome of pelvic sepsis was analyzed in 210 patients who underwent restorative proctocolectomy for ulcerative colitis (UC) in 197 patients, and for familial adenomatous polyposis (FAP) in 13 patients. Pelvic sepsis developed in 18 patients (8.6%) and a significantly higher incidence was seen in men than in women, at 13.6% vs 3.7%, respectively (P < 0.05). The incidence of pelvic sepsis in patients with UC complicated by toxic megacolon and/or fulminant colitis was significantly higher that in those without any preoperative complications, at 36.4% vs 7.4% (P < 0.05). The incidence of pelvic sepsis following handsewn anastomosis was significantly higher than that following stapled anastomosis, at 15.6% vs 5.5% (P < 0.05). The outcome of pelvic sepsis in patients with a stapled anastomosis was better than that in those with a handsewn anastomosis. The prognosis of women who developed pelvic sepsis was better than that of men who developed pelvic sepsis. The risk factors predisposing to pelvic sepsis were UC, especially when complicated by toxic megacolon and/or fulminant colitis, and male sex, while a handsewn anastomosis was more vulnerable than a stapled anastomosis.