Abstract: Objective: To investigate the expression and clinical significance of resistance-related genes in non-small cell lung cancer tissue. Methods: Expression of P-glycoprotein (P-gp), multidrug resistance -associated protein(MRP), lung resistance pretein(LRP), glutathione Stransferases (GST) and DNA topoisomerase II (Topo) in lung carcinoma tissue from untreated patients was measured by im-munohistochemistry technique. Results: The Positive rates of P-gp, MRP, LRP, GST-π and Topo II which were negative or weakly positive in the normal pericarcinoma tissues and expressed together in part of samples among 58 untreated patients were 96.55%, 67.24%, 75.86%, 65.52R and 98.28R re-spectively, which were not markedly correlated to sex, smoke history, TNM staging, differentiated degree and lymph node metastasis (P>0.05). There were statistic difference in MRP, LRP and GST-π expression(P<0.05) and no marked difference in P-gp and Topo II between squamous carcinoma and adeno-carcinoma (P>0.05). Conclusion: Multidrug resistance of lung cancer is a process involved in polygene and multiple pathways, which is more common in adenocarcinoma compared with squamous carcinoma Combined examination of resistance-related genes in lung cancer tissues is helpful to the judgement of chemotherapeutics effects and prognosis.