Purpose: Colorectal cancer (CRC) is the fifth most common cause of cancer deaths in China and fourth worldwide. Metastatic dissemination of primary tumors is considered main cause for CRC related mortality. The serine-threonine kinase 31 (STK31) gene is a novel cancer testis (CT) antigen. It was found significantly highly expressed in gastrointestinal cancers. In our study we aimed to analyze the correlation between STK31 expression patterns and metastasization, tumor stage and grade in CRC patients. Results: Relative STK31 expression level was significantly higher in patients with lymph node metastasis. STK31 expression levels in primary tumorous tissues of metastatic patients were significantly higher than in ANCTs and in lymph nodes samples, both at the RNA level and the protein level. Materials and Methods: Surgical specimens of cancerous tissues, paired with adjacent noncancerous tissues, and lymph nodes from 44 CRC cases with different clinicopathological features were collected. Expression of STK31 was detected and measured by immunohistochemistry and quantitative real-time polymerase chain reaction (QRT-PCR). Conclusions: Our data suggest that STK31 might be a potential biomarker in detecting, monitoring and predicting the metastatic risk of colorectal cancer.