Tumor suppressor in lung cancer 1 (TSLC1), a novel tumor suppressor gene, has been reported to be frequently inactivated in a variety of human malignant tumors. The aim of this study was to detect TSLC1 expression in human colon cancer and to analyze its association with prognosis of patients with colon cancer. Using quantitative real-time PCR and Western blot analysis, we found significantly decreased expression of TSLC1 in primary colon tumor tissues (n = 30) compared with adjacent normal tissues. Immunohistochemistry analysis also found decreased TSLC1 expression in 41.3 % (33/80) colon tumor tissues. In clinicopathological analysis, loss of TSLC1 expression significantly correlated with female gender and lymph node metastasis of colon cancer patients (P < 0.05). In addition, decreased expression of TSLC1 in tumors was found to be closely associated with a poor prognosis (P = 0.037, log-rank test), and multivariate analysis showed that lower TSLC1 protein expression was an independent prognostic factor for colon cancer patients. Our study suggests that down-regulated expression of TSLC1 may play an important role in the progression of colon cancer and TSLC1 expression may serve as a useful marker for the prognostic evaluation of patients with colon cancer.