Objective To investigate the levels of miR-1 9a and miR-1 9b expressions in cancer tissues and serum of patients with non-small cell lung cancer (NSCLC),and evaluate the potential of miR-1 9a and miR-1 9b as biomarkers of NSCLC.Methods Real time-PCR was used to detect the expressions of miR-1 9a and miR-1 9b in serum of normal people and patients with NSCLC and in cancer tissues and their corresponding non-tumor tissues. The diagnostic value of miR-1 9a and miR-1 9b for NSCLC was assessed by receiver operator characteristic (ROC) curve.Results The expression levels of serum miR-1 9a and miR-1 9b were significantly higher in patients with non-small cell lung cancer than in normal people (P <0.05 ).The expressions of miR-1 9a and miR-1 9b in NSCLC were much higher than in the adjacent normal tissues.For miR-1 9a the area under ROC curve was 0.989,and the sensitivity and specificity were 95.1 and 94.0.The area under ROC curve for miR-1 9b was 0.983,and the sensitivity and specificity were 93.4 and 94.0.Conclusion The high expressions of miR-1 9a and miR-1 9b are found in cancer tissues and serum from NSCLC patients.Therefore,they may be used as noninvasive biomarkers for diagnosis and prognosis of NSCLC.