Abstract: Objective :To study the relationship between the expression of MDR1? LRP gene and the clinical pathophysiological characteristics of lung cancer tissues aswell as in the lung cancer cell lines. Methods : Total RNAs were extracted from 46 cases of patients with lung cancer, and 4 lung cancer cell lines (A549, GLC-82, NCI-H446, NCI-H460), MDR1, LRP gene expressions were detected at mRNA level by reverse transcription-polymerase chain reaction (RT-PCR). Results : MDR1 and LRP gene were positively expressed in 18 (39.1%) and 31(67.4%) of 46 lung cancer patients, respectively, and they were positive expressed concomitantly in 12(26.1%)lung cancer patients. The frequency expression of MDR1 in squamous, adenocacinomas, small cell lung cancer, high-middle differentiation and low differentiation were 31.6%, 44%, 50%, 44%, 33.3%, respectively; the positive rate of LRP in squamous, adenocacinomas, small cell lung cancer, high-middle differentiation and low differentiation were 63%, 76%, 0, 72%, 62.0% respectively; The frequency expression of MDR1 and LRP gene did not vary with the lung cancer histology type and the grade of cell differentiation (P>0.05). MDR1 gene was positively expressed in A549, GLC-82, NCI-H446, NCI-H460 cell lines, LRP gene was positively expressed in A549, GLC-82, NCI-H460 cell lines. Conclusion : MDR1 and LRP gene are expressed in lung cancer tissues and lung cancer cell lines, indicating the presence of intrinsically drug resistance before any form of therapy, and the expression of MDR1 and LRP gene does not vary with the lung cancer histology type and the grade of cell differentiation. These results suggest that this procedure might be applied to the future gene therapy of lung cancer.