Background: The aim of this study was to identify factors that predict morbidity and mortality in gastric cancer surgery. Methods: Data on 719 consecutive patients who underwent operations for gastric cancer at Seoul National University Hospital between January and December 2002 were reviewed. Results: Overall morbidity and mortality rates were 17.4 per cent (125 patients) and 0.6 per cent (four patients) respectively, and the rates of surgical and non-surgical complications were 14.7 per cent (106 patients) and 3.3 percent (24 patients). Morbidity rates were higher in patients aged over 50years (odds ratio (OR) 1.04 (95 per cent confidence interval (c.i.) 1.02 to 1.06)), when the gastric tumour was resected with another organ (36 per cent for combined resection versus 15-4 per cent for gastrectomy only; OR 3.25 (95 per cent c.i. 1.76 to 6.03)) and when gastrojejunostomy was used for reconstruction after subtotal gastrectomy (17.0 per cent for Billroth II versus 9.5 per cent for Billroth I; OR 2-00 (95 per cent c.i. 1.05 to 3.79)). Only three patients (2-8 per cent) with a surgical complication underwent reoperation, two for adhesive obstruction and one for intra-abdominal bleeding. Conclusion: Age, combined resection and Billroth reconstruction after radical subtotal gastrectomy were independently associated with the development of complications after gastric cancer surgery.