CD133, CD44, and CD166 are cell surface markers that have recently been associated with colorectal cancer stem cells. As which of these markers has the greatest impact on patient prognosis is currently unknown, we compared their expression and prognostic significance in 110 colorectal adenocarcinomas. We demonstrate that expression of CD133 correlates with that of CD166, while both do not correlate with CD44. We show that CD133 is the best sole marker to predict low patient survival, while the combined analysis of all three markers may be superior in identification of low-, intermediate-, and high-risk cases of colorectal cancer.