Colorectal cancer (CRC) patients with peritoneal carcinomatosis (PC) have a poor prognosis. Over the last decade, increasing evidence has suggested that the Collagen Triple Helix Repeat Containing 1 (CTHRC1) gene is involved in cancer progression and invasion. In this study, we investigated the expression of CTHRC1 in CRC and its potential as a prognostic factor for CRC patients with PC. Microarray analysis of four fresh paired samples showed that the expression of CTHRC1 in peritoneal metastases was higher than that in the corresponding primary tumor. These results were validated using semi-quantitative reverse transcription and polymerase chain reaction. Finally, immunohistochemical analysis showed that CTHRC1 was increased in the peritoneal metastasis group (n = 30) and the primary cancer with peritoneal metastasis group (n = 57) compared to the primary cancer without peritoneal metastasis group (n = 54), both P < 0.001. Cox proportional hazards model analysis showed that high CTHRC1 expression was associated with poor survival (HR = 2.754, P < 0.001, 95 % CI 1.731-4.383). Overall, the results of our study suggest that increased expression of CTHRC1 is associated with PC in CRC patients and could predict poor outcome in CRC patients.