The corneal epithelial cells are the outermost layer of the cornea. When they are turnover or trauma, the corneal epithelial cells are supplemented by continuous self-renewal of stem cells located in the basal epithelium at the corneoscleral limbus. If limbal stem cells are deficient(LSCD), this balance would be broken, resulting in corneal diseases. Currently, transplantation of cultured limbal stem cells is one of the best curative option of reconstruction of the ocular surface. This article reviews the recent progress on identification, different sources of stem cells, and expansion of limbal stem cells.