Of 1165 patients with stomach cancer included in a national, prospective multicenter study with 51 surgical units participating, information about weight loss before diagnosis was available for 855 patients (73%). Median weight loss was 5 kg; 259 patients (31%) experienced no weight loss. By logistic regression analysis the authors found that weight loss increased with age and advancing stages of disease (TNM Stage I-IV), with decreasing Karnofsky index, in Lauren's diffuse versus intestinal tumor type, and with tumors located at the cardia/esophagus. Increasing weight loss reduced the resectability rate significantly, but no association between weight loss and postoperative complication rate was found. The odds ratio for postoperative mortality was 2.5 to 1 for the weight loss group 5 to 10kg versus 0 kg. In conclusion, weight loss reflects a less favorable tumor status. Weight loss did not increase postoperative morbidity but did lead Weight to a higher death rate after surgery.