Abstract. This study aimed to evaluate the biological functions of excision repair cross complementation goup 1 (ERCC1) in cell proliferation, cell cycle, invasion and cisplatin response of non-small cell lung cancer (NSCLC) cells. Firstly, ERCC1 gene was successfully transfected into H1299 cells by gene cloning and transfection techniques. Then, cell proliferation was determined with the cell growth curve and colony-forming assays. Flow cytometry (FCM) was employed to investigate the cell cycle distribution. The ability of cell invasion was estimated by means of Matrigel invasion assays. Response of NSCLC cells to cisplatin was detected utilizing MTT assays, and the intracellular drug concentrations were determined by the high performance liquid chromatography (HPLC) analysis. Expression of the two cell membrane proteins, P-glycoprotein (P-gp) and multidrug resistanceassociated protein (MRP), was also evaluated utilizing FCM technique. By contrast, ERCC1 expression in the NSCLC A549 cells was silenced by small interfering RNA (siRNA) through RNAi technique. In addition, the cytotoxic effect of cisplatin on A549 cells was detected by MTT assays. In the present study, the results demonstrated that ERCC1 had no effect on cell proliferation, cell cycle and the ability of invasion, but showed significant impact on cisplatin response of the NSCLC H1299 cells. Furthermore, siRNA-induced suppression of ERCC1 evidently enhanced sensitivity to cisplatin of NSCLC A549 cells. Therefore, it is confirmed that ERCC1 is a chemotherapy-tolerating gene and a promising predictor in tailoring chemotherapy of NSCLC.