AIM: The aim of the present study was to explore the association between CD133 expression and postoperative relapses in patients with locally advanced rectal cancer (LARC) who received neoadjuvant chemotherapy (NAC). PATIENTS AND METHODS: We retrospectively examined 52 patients with LARC (cT3-4, Nany, M0) who received oxaliplatin-based NAC before surgery. CD133 expression was evaluated using immunohistochemistry and divided into low and high expression groups. RESULTS: High CD133 expression was observed in 22 patients (42.3%). Patients with high CD133 expression had more frequent vessel invasion and relapse than those with low CD133 expression (p=0.013 and p=0.036, respectively). Comparing the low with high CD133 expression groups, the 4-year relapse-free survival rates were 82.2% vs. 46.3% (p=0.009). Multivariate analysis indicated that CD133 expression was an independent risk factor for relapse (HR=3.138; 95%CI=1.046-9.412; p=0.041). CONCLUSION: CD133 expression may be a predictive biomarker for postoperative relapse in patients with LARC who received NAC before surgery.