Metastasis-associated protein 1 (MTA1 protein) has been reported to be correlated with the biological behavior and prognosis of several malignant carcinomas. We hypothesized that stage I non-small cell lung cancer (NSCLC) patients with MTA1 protein overexpression would be more likely to have a poor prognosis. Therefore, we tested the expression of MTA1 protein in 60 stage I NSCLC and 30 paracarcinous normal lung tissues using the streptavidin-perosidase method. The Kaplan-Meier method was used to calculate the survival rate, and Cox regression analysis was performed to identify prognostic risk factors. MTA1 protein overexpression was detected in 22 stage I NSCLC tissues in this study. Tumor differentiation and tumor diameter were significantly associated with MTA1 protein overexpression, while not correlated with age, sex, pathological type or smoking status. The five-year survival rate of patients with MTA1 protein overexpression was significantly lower than that of those without expression (40.9% vs. 84.1%; P<0.001). The results of multivariate analysis confirmed that MTA1 protein overexpression was an independent prognostic factor (risk ratio=5.23, P=0.007). These findings demonstrated MTA1 might be a prognostic factor in NSCLC.