In a prospective multicentre study of 2394 patients with gastric carcinoma the prognostic relevance of systematic lymph node dissection was evaluated. Of 1654 patients undergoing resection, 558 had a standard lymph node dissection, defined as fewer than 26 nodes in the specimen, and 1096 underwent radical lymphadenectomy, i.e. 26 or more nodes in the specimen. Radical dissection signficantly improved the survival rate in patients with Union Internacional Contra la Cancrum (UICC) stages II and IIIA tumours. Multivariate analysis identified radical dissection as an independent prognostic factor in the subgroups of patients with UICC tumour stages II and IIIA. Radical dissection conferred no survival advantage in patients with pN2 tumours. There was no significant difference in morbidity and mortality rates between radical and standard lymph node dissection. Radical lymphadenectomy improves survival in patients with UICC gastric cancer stages II and IIIA, and should be the recommended treatment for such patients.