Abstract: Objective To investigate the clinical significance of detecting MMP-2mRNA and MMP-14mRNA with peritoneal lavage fluid in patients with gastric cancer.Methods The ex-pression of 98 patients of MMP-2mRNA and MMP-14 mRNA in peritoneal lavage fluid were de-teced by RT-PCR in patients with gastric cancer.30 patients with benign peritoneal lavage fluid were in the negative control group.Results The positive expression rates of MMP-2mRNA and MMP-14mRNA in the peritoneal lavage fluid in patients with gastric cancer were 42 /98(42.9%) and 40 /98(40.8%).but they were 2 /30(6.67%)、3.33% (1 /30)respectively in normal control (P <0.01).The positive expression rate of MMP-2mRNA and MMP-14mRNA were related to the depth of invasion,peritoneal metastasis,macroscopic type (P <0.01).Conclusion RT-PCR de-tection on the expression of MMP-2mRNA and MMP-14mRNA in peritoneal lavage fluid in patients with gastric cancer can be used to predict the peritoneal metastases.MMP-2 and MMP-14 may be involved in the peritoneal metastasis process.