Peritoneal lavage was performed in 66 patients with gastric carcinoma to assess the amount of free tumor cells. 12/66 patients (18 %) proved to have free cancer cells. The intestinal type of carcinoma showed more frequently free tumor cells (8/12). There was no correlation between free cancer cells and the number of invaded lymph nodes. Patients with curative surgery but free cancer cells belong to the risk groups for early recurrences. Whether surgery on its own causes an increase in free tumor cells needs to be studied as well as the potential benefit of adjuvant chemotherapy in these patients.