Objective: To investigate the relations of pleiotrophin (PTN) expression and its serum level with colorectal cancer. Methods: The PTN mRNA and protein expression in tumor tissue specimens of 46 cases of colorectal cancer and in their adjacent tissue was determined by real-time PCR and Western blot, respectively, and the PTN level in the blood samples from 76 patients with colorectal cancer and 58 subjects undergoing health maintenance examination was measured by ELISA assay. Results: Both the PTN mRNA expression level and PTN protein positive expression rate in colorectal cancer tissue were significantly higher than those in the adjacent normal tissue (both P<0.05), and either the PTN mRNA expression level or PTN positive rate was not associated with age of the patients or histological type of the tumor (all P>0.05), but showed a significantly negative relation with TNM classification (all P<0.05).The serum PTN level in colorectal cancer patients was significantly higher than that in normal subjects (P<0.05). Conclusion: PTN expression is increased in colorectal cancer tissue and serum PTN level may be used as one of the diagnostic tests for colorectal cancer.