Abstract: ObjectiveIn o rder to examine the relationship between glutathiones-transferase M1,T1(GSTM1,GSTT1)genetic polymorphism and susceptibility to gastric cancer.MethodsA case-control study was carried out and polymerase chain reaction (PCR)technique was used to identify GSTM1,GSTT1 genoty pe in 89 cases of primary gastric cancer and 94 controls.ResultsThe frequency of GSTM1 null genotype in patients with gastric cancer(61.8%)showed a statistically significant increase compared to the control group frequency(46.8%)(χ²=4.14,P=0.042, OR=1.84,95% CI=1.02~3.31);the frequency of GSTT1 null genotype in cased(57.3%)was also higher than it in controls, but this increase did not reach statistical sig nificance(χ²=1.28,P=0.257,OR=1.40,95% CI=0.78~2.51);the risk for gastric cancer in those with GSTM1 nun and GSTT1 null genoty pe was significantly higher than that in those with GSTM1 non-null and GSTT1 non-null genotype,with the OR of 2.27 and 95% CI of ORs 1.06~4.85;the risk for gastric cancer in those smoking with GSTM1 null genot ype increased significantly(OR=3.09,95% CI=1.33~7.19).ConclusionGSTM1 null genotype is associated with the risk for gastric cancer;the individuals with GST M1(-)and GSTT1(-)are more susceptibility to gastric cancer;GSTM1 and smoke may cooperate with each other in the occurrence and development of gastric cancer.