Objective: This study aims to evaluate the mRNA levels of solute carrier family 22, member 17 (SLC22A17) and its potential clinical value as a diagnostic and prognostic biomarker in non-small cell lung cancer. Methods: This prospective study measured SLC22A17 mRNA levels in lung cancer and paracancer tissues using quantitative reverse transcription-polymerase chain reaction (PCR). The levels of SLC22A17 mRNA in plasma samples from healthy control subjects and patients with lung cancer were also measured. The association between SLC22A17 mRNA levels in plasma and clinicopathological characteristics was determined. Receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic value of SLC22A17 in plasma. Survival curve analysis was performed using the Kaplan-Meier method. Results: SLC22A17 mRNA levels were significantly higher in lung cancer samples than in the paired paracancerous tissues. Plasma SLC22A17 mRNA levels were also significantly higher in patients with lung cancer than in healthy controls. The COX analysis indicated that there was a significant correlation between elevated plasma SLC22A17 mRNA levels and lymph node metastasis, distant metastasis, and TNM stage. Furthermore, the ROC curve analysis demonstrated that plasma SLC22A17 had high diagnostic value. High plasma SLC22A17 mRNA levels are associated with a significantly shorter survival time. Conclusion: SLC22A17 is upregulated in lung cancer and may serve as a novel diagnostic and prognostic biomarker