Objective: This study was set out to inquire into the expression and clinical significance of lncRNA activated by transforming growth factor beta (LncRNA-ATB) and in cancer tissues of patients with non-small cell lung cancer (NSCLC). Methods: LncRNA-ATB in cancer tissues and adjacent tissues of 89 NSCLC patients was detected by quantitative real-time polymerise chain reaction (qRT-PCR), and its clinical diagnostic value in NSCLC was determined by receiver operating characteristic (ROC) curves. Based on the median expression of LncRNA-ATB in NSCLC tissues, 89 patients were allocated into high- and low-expression groups. The 3-year survival rate was calculated using Kaplan-Meier method and logrank test, and compared between lncRNA-ATB high and low expression groups by Log-rank test. Cox regression quantitatively analyzed the correlation between lncRNA-ATB and the clinical prognosis of NSCLC patients. Results: LncRNA-ATB presented notably higher expression in NSCLC tissues as compared to adjacent tissues (P < 0.05), and was linked to smoking history, TNM stage and greatest tumor diameter (GTD) (P < 0.05). The cut-off value, sensitivity and specificity, as well as the area under the curve (AUC) of NSCLC diagnosed by LncRNA-ATB were 2.103, 73.77%, 83.15% and 0.836, respectively. Patients with high lncRNA-ATB expression (40.00%) showed statistically lower than those with low lncRNA-ATB expression (63.36%). TNM stage, differentiation degree and lncRNA-ATB expression were independent variables affecting patient prognosis. Conclusions: LncRNA-ATB, with increased expression profiles in NSCLC tissues, is involved in NSCLC progression and associated with unfavourable prognosis of patients, which can be a plausible tumor marker for NSCLC patients.