['MicroRNA-124 (miR-124) has been proven dysregulated in several human malignancies and correlated with tumor progression. However, its expression and clinical significance in non-small cell lung cancer (NSCLC) is still unclear. Thus, the aim of this study was to investigate the clinical significance of miR-124 expression in NSCLC.', 'Expression levels of miR-124 in 92 pairs of NSCLC and adjacent non-tumor tissues were detected by quantitative real-time PCR (qRT-PCR). In order to determine its prognostic value, overall survival (OS) and disease-free survival (DFS) were evaluated using the Kaplan-Meier method, and multivariate analysis was performed using the Cox proportional hazard analysis.', 'miR-124 expression level was significantly lower in NSCLC tissues compared with adjacent non-tumor tissues (P < 0.05). The 5-year OS of low miR-124 expression group was significantly shorter than that of high miR-124 expression group (P < 0.05). Moreover, the 5-year DFS of low miR-124 expression group was also significantly shorter than that of high miR-124 expression group (P < 0.05). In a multivariate Cox model, we found that miR-124 expression was an independent prognostic factor for both 5-year OS and 5-year DFS in NSCLC (P < 0.05).'] Is down-regulation of microRNA-124 correlated with tumor metastasis and poor prognosis in patients with lung cancer?