Previous studies have suggested that dysregulation of microRNA (miR) -124a is associated with various types of human cancer. However, there are few studies reporting the level of miR‑124a expression in non‑small cell lung cancer (NSCLC). The present study investigated the association between miR‑124a and NSCLC by analyzing the differential expression of miR‑124a in NSCLC using the GEO database, as well as subsequently performing reverse transcription‑quantitative polymerase chain reaction analysis on 160 NSCLC biopsies, 32 of which were paired with adjacent normal tissues. The results indicated that mir‑124a expression levels were decreased in NSCLC tumor biopsies compared with adjacent normal tissues. The overall survival (OS) in patients with a high expression of miR‑124a was prolonged relative to patients with low expression of miR‑124a. The expression levels of miR‑124a were associated with clinical characteristics, including lymph‑node metastasis, tumor differentiation, tumor node metastasis (TNM) stage and diameter. Frequently, lymph‑node metastasis, TNM stage, diameter and lack of chemotherapy have been associated with a worse prognosis in patients. In addition, the present study identified that high expression of miR‑124awith chemotherapy may increase OS. In conclusion, the current study demonstrated that miR‑124a was downregulated in NSCLC, and miR‑124a was a potential prognostic tumor biomarker response to chemotherapy.