Background: Non-small cell lung cancer (NSCLC) is a highly aggressive malignancy with increasing incidence across the world. The role and mechanism of circular RNAs (circRNAs) in the pathogenesis of NSCLC have not been understood exactly. In this work, we aims to explore a novel NSCLC-associated circRNA, circ_0003645. Methods: The expression profile of circ_0003645 was evaluated in NSCLC tissue specimens and cells. Additionally, the correlation between circ_0003645 and clinical features/patients' prognosis were investigated. Functionally, CCK-8, clone formation, flow cyometric and transwell assays were performed in two cell lines. Furthermore, dual-luciferase reporter and rescue experiments were carried out to elucidate the mechanism of circ_0003645. Results: The data demonstrated an upregulation of circ_0003645 in patients' tissue specimens and cells. Overexpression of circ_0003645 in tissues was related to advanced TNM stages, positive lymph node invasion and unfavorable prognosis for the patients with NSCLC. In addition, gain and loss of function assays uncovered that circ_0003645 functioned as an oncogene in NSCLC cells. Moreover, circ_0003645 acted as a ceRNA to sponge miR-1179, which resulted in the elevation of TMEM14A expression and facilitated cell progression. Conclusions: This study indicates that circ_0003645 might possess crucial potential as a prognosis predictor and therapeutic target for NSCLC patients. (C) 2019 Elsevier Inc. All rights reserved.