Abstract: The present invention relates to fibulin-3 protein and a pharmaceutical composition comprising the fibulin-3 protein as an active ingredient for inhibiting the growth of cancer stem cells. More particularly, in cancer stem cells separated from H460 and A549 cells, which are non-small-cell lung cancer cells, using ALDH1 activity as a marker, fibulin-3 induces the reductions of wnt/?-catenin, MMP2 and 7, which display characteristics of cancer stem cells, thereby decreasing the activated growth and penetration of the cancer stem cells. In addition, the purified fibulin-3 protein inhibits the growth of the non-small-cell lung cancer cell line A549, the breast cancer cell line MDA-MB231, and the cancer stem cell line active ALDH1. Therefore, fibulin-3 can be valuably used as an active ingredient of the pharmaceutical composition for inhibiting the growth of cancer stem cells.