Objective To investigate the correlation between expression of carcinoembryonic antigen (CEA) mRNA in preoperative peritoneal lavage fluid and prognosis of operation in patients with gastric cancer.Methods The expression levels of CEA mRNA in preoperative peritoneal lavage fluid of 68 patients with gastric cancer and 30 patients with gastric benign tumor were measured by reverse transcription polymerase chain reaction.The correlation between the expression level of CEA mRNA in preoperative peritoneal lavage fluid and clinicopathological features,prognosis of postoperative were analyzed.Results The expression level of CEA mRNA in preoperative peritoneal lavage fluid of patients with gastric cancre was 1.74 ± 0.25 and with gastric benign tumor was 0.19 ± 0.04,and there was statistical difference (P ＜ 0.05).The expression level of CEA mRNA in preoperative peritoneal lavage fluid had a correlation with the tumor infiltration depth,tumor differentiation,lymph node metastasis,distant metastasis and TNM stage (P ＜ 0.05).There was statistical difference in the recurrent / metastasis rate and survival rate 1 year after operation between low (34 cases) and higher (34 cases) expression level of CEA mRNA in preoperative peritoneal lavage fluid of gastric cancer patients:47.06％ (16/34) vs.82.35％ (28/34) and 79.41％ (27/34) vs.55.88％ (19/34),P ＜ 0.05.Conclusion The expression of CEA mRNA in preoperative peritoneal lavage fluid has close correlation with the clinicopathologic features,and the high expression of CEA mRNA indicats poor prognosis,indicating that CEA mRNA in preoperative peritoneal lavage fluid could be used as a prognostic marker in patients with gastric cancer.