Objective:The aim of the study was to investigate the relationship of DNA ploidy status in colorectal cancers with patients' prognosis and also the relationship of DNA ploidy status with expression of the colorectal cancer stem cell marker CD133.Methods:The DNA ploidy status and CD133 expression in colorectal cancers were detected by flow cytometry.The clinicopathological characteristics and progression-free survival analysis of patients was evaluated based on the clinical data.Results:DNA ploidy pattern did not correlated with gender,age,lesion diameter,histological type,depth of tumor invasion,lymphatic invasion and Dukes stage.Only primary lesion cite showed significant correlation with DNA ploidy pattern,more aneuploids were observed in colonic cancer than rectal cancer,P < 0.05.The 2-year progression-free survival rate and total progression-free time in patients with aneuploids were lower than that with diploids,P < 0.05.Tumors contained aneuploids showed higher expression of CD133 than tumors of only diploids,P < 0.05.Conclusion:Tumor DNA ploidy status is a significant prognostic factor in patients with colorectal cancer and also associated with the existence of CD133 positive colorectal cancer stem cells.