Objective:To investigate the expressions of thymidine kinase 1(TK1) and Ki-67 in non-small cell lung cancer(NSCLC)and their prognostic value in NSCLC. Methods:The tissue microarrays which contain 202 NSCLC cases and 63 normal lung cases were constructed. The expressions of TK1 and Ki-67 were detected in these tissues by immunohistochemistry method. The relationship between expression levels of two makers and the clinicopathological and survival parameters of NSCLC were evaluated. Results:The positive expression rates of TK1(60.89%)and Ki-67(55.45%)in the NSCLC tissues were significantly higher than those in normal tissue group (P < 0.000 1,P < 0.000 5). The Spearman correlation analysis showed that the expression of TK1 were positively correlated with Ki-67 expression (r = 0.518,P < 0.001). In the group of NSCLC, both TK1 and Ki-67 expression were significant correlated with tumor grade and TNM stage. Kaplan-Meier survival analysis indicated that the survival rate was markedly lower in patients with high expression level of two markers than those with low expression level (P < 0.05);Multivariate analysis using Cox regression model identified that TNM stage and TK1 expression were independent prognostic factors of NSCLC (P < 0.05). Conclusion:The expression of TK1 was significantly correlated with tumor grade and TNM stage. TK1 might be employed to evaluate the prognosis of NSCLC patients.