Recently increasing reported data have suggested that only a small subset of cancer cells possess capability to initiate malignancies including leukemia and solid tumors, which was based on investigation in these cells displaying a distinct surface marker pattern within the primary cancers. CD133 is a putative hematopoietic and neuronal stem‐cell marker, which was also considered as a tumorigenic marker in brain and prostate cancer. We hypothesized that CD133 was a marker closely correlated with tumorigenicity, since it was reported that CD133 expressed in human fetal liver and repairing liver tissues, which tightly associated with hepatocarcinogenesis. Our findings showed that a small population of CD133 positive cells indeed exists in human hepatocellular carcinoma (HCC) cell lines and primary HCC tissues. From SMMC‐7721 cell line, CD133⁺ cells isolated by MACS manifested high tumorigenecity and clonogenicity as compared with CD133⁻ HCC cells. The implication that CD133 might be one of the markers for HCC cancer stem‐like cells needed further investigation. © 2006 Wiley‐Liss, Inc.