Objective:To identify and isolate CD133 positive cancer stem-like cells (CD133+ cells) from the highly invasive human hepatocellular carcinoma cell line(MHCC97H), and examine their potential for clonogenicity and tumorigenicity. Methods: CD133+ and CD133- cells were isolated from MHCC97H cell line by magnetic bead cell sorting(MACS), and the potentials of CD133+ cells for colony formation and tumorigenicity were evaluated by soft agar cloning and tumor formation following nude mice inoculation. Results:CD133+ cells represent a minority(0.5-2.0%) of the tumor cell population with a greater colony-forming efficiency and greater tumor production ability. The colony-forming efficiency of CD133+ cells in soft agar was significantly higher than CD133- cells(36.8±1.4 vs 12.9±0.8, P ＜0.05). After 6 weeks, 3/5 mice inoculated with 1×103 CD133+ cells, 4/5 with 1×104 CD133+ cells and 5/5 with 1×105 CD133+ cells developed detectable tumors at the injection site, while only one tumor was found in mice treated with same numbers of CD133- cells. Conclusion: CD133 may be a hallmark of liver cancer stem cells (CSC) in human hepatocellular carcinoma(HCC), because the CD133+ cells identified and isolated with anti-CD133 labeled magnetic beads from MHCC97H cell line exhibit high potentials for clonogenicity and tumorigenicity. These CD133+ cells might contribute to hepatocarcinogenesis, as well as the growth and recurrence of human HCC, and therefore may be a useful target for anti-cancer therapy.