Abstract: Objective To explore the susceptibility of lung cancer in relation to cytochrome P4501A1A(CYP1A1) and glutathione S-transferase theta1(GSTT1) genetic polymorphisms.Methods CYP1A1 and GSTT1 genetic polymorphisms were determined with allele specific polymerase chain reaction(AS-PCR) and multiplex PCR in 106 lung cancer patients and 250 healthy people.Results The individuals who carried with CYP1A1(Val/Val)/GSTT1(-) had a high risk of lung cancer(P=0.025).Statistical tests showed that susceptibility to lung cancer was related to smoking(P=0.037).The risk of lung cancer in smoking individuals raised remarkably(odds ratioOR=1.628,95% confidence intervalCI:1.028-2.577).The smokers with CYP1A1(vt/vt) had a significantly higher risk of lung cancer than nonsmokers with CYP1A1(Ile/Ile)(P=0.033).A significantly higher risk of lung cancer was also found in the smokers with GSTT1(-)(P=0.045).Conclusion The polymorphisms of CYP1A1(vt/vt) and GSTT1(-) may be the suspicious risk factors for lung cancer.There is a synergetic interaction between CYP1A1(vt/vt) and GSTT1(-) on the elevated susceptibility of lung cancer.The CYP1A1(vt/vt),GSTT1(-) and smoking have a cross-promotive effect on lung cancer incidence.