Objective: The new concept of cancer stem cells has implications in terms of possible application for novel diagnostic and therapeutic procedures. Recently, the CD133 molecule was reported as a marker of cancer stem-like cells in colorectal cancer (CRC). In this study, we examined the prognostic value of free cancer cells in peritoneal washings from CRC patients after curative resection using multiple molecular markers, including cancer stem-like cells. Methods: A total of 170 CRC patients who had undergone curative surgery were studied. Peritoneal washings of the Douglas cavity were collected and used for cytology and molecular diagnosis. Real-time RT-PCR for carcinoembryonic antigen (CEA), cytokeratin 20 (CK20) and CD133 mRNA was performed to detect free cancer cells. Results: Molecular detection of CEA, CK20 and/or CD133 (CEA/CK20/CD133) mRNA of the peritoneal washings showed a significant correlation with lymph node metastasis and the tumor stage. The overall survival (OS) rates and peritoneal recurrence-free survival (PFS) rates in CEA/CK20/CD133 mRNA-positive patients were significantly lower than those of marker gene-negative patients. CD133/CEA/CK20 mRNAs in peritoneal washings were independent prognostic factors for OS and PFS. Conclusion: Molecular detection of free cancer cells using multimarkers, including cancer stem-like cells in peritoneal washings of post-curative surgery CRC patients, are useful in prognosis prediction.