Background Peritoneal dissemination is the most common pattern of metastasis in advanced gastric carcinoma with serosal invasion In the present study, we reported the clinical relevance of a new diagnostic method involving RT-PCR, using su rvivin as the target gene, for the detection of free cancer cells in peritoneal washes Methods Intraoperative peritoneal washes were obtained from 48 patients who underwent su rgery for gastric cancer RT-PCR analysis with primers specific for survivin and conventional cytological examinations were both performed Results Su rvivin mRNA was not detected in any peritoneal wash samples from patients with benign disease, but was detected in 28 of 48 samples taken from patients with gastric cancer and in all metastastic nodules Survivin expression in the peritoneal cavity significantly correlated with depth of cancer invasion, lymph node etastasis, and TNM stage There were 92% of clinically evident peritoneal metastasis cases showed detectable su rvivin expression The combination of survivin RT-PCR and cytological examination yielded positive results in 66 7% (32/48) of patients with gastric cancer, much higher than the results produced by cytological method alone Conclusions Survivin mRNA detected in peritoneal lavage fluid might indicate the presence of free cancer cells in the peritoneal cavity. The high sensitivity of the RT-PCR-based survivin assay suggests that su rvivin serves as a molecular marker for detecting peritoneal micrometastasis Its ubiquitous expression in peritoneal cancer cells and metastatic nodules also suggests a promising future therapeutic strategy based on su rvivin inhibition for cases of gastric cancer involving peritoneal metastasis