To evaluate risk factors, results of treatment, and prognostic influence of complications on survival from acute necrotising pancreatitis. Retrospective study of prospectively collected data. Tertiary referral centre, Austria. 100 consecutive patients operated on for necrotising pancreatitis confirmed by dynamic angio-computed tomography from 1988-1997. 77 patients were operated on acutely followed by open management, and in 23 the operations were delayed. Morbidity, mortality, factors predisposing to complications, prognostic effect of complications on survival. Acute operations, alcoholic origin, APACHE II scores of > or = 10 on admission, and organ dysfunction on admission were independent factors that predisposed patients to complications. Colonic necrosis (n = 17) bleeding (n = 12) and intestinal fistulisation (n = 10) predominated. The overall mortality of complicated pancreatic necrosis was higher among patients admitted with surgical complications than in those who were not, but not significantly so (12/33 compared with 7/44 p = 0.06). Colonic necrosis (mortality 53%, relative risk: 2.45, p = 0.01), however, seemed to be of prognostic relevance. Complications are common in severe necrotising pancreatitis leading to organ dysfunction and need for acute operations. Colonic necrosis is an independent prognostic factor for survival.