Background: Keratinocyte stem/progenitor cells (KSCs) reside in the bulge region of the hair follicles and may be involved in hair growth and regeneration. Objectives: We studied the hair growth promotion effects of KSC-CM on human HF organ culture and on a C3H/HeN mouse model. We then investigated the proliferative effect of KSC-CM on both human hair follicle dermal papilla cells (HFDPCs) and outer root sheath (ORS) cells. Methods: Hair follicle dermal papilla cells (HFDPCs) and outer root sheath (ORS) cells were treated with conditioned medium (CM) of KSCs. Moreover, the effects of KSC-CM on hair growth were examined ex vivo and in vivo. A human growth factor chip array and RT-PCR were employed to identify enriched proteins in KSC-CMas compared with CM from keratinocytes. Results: KSC-CM increased the proliferation of HFDPCsand ORS cells, and increased the S-phase of the cell cycle in HFDPCs. After subcutaneous injection of KSC-CM in C3H/HeN mice, a significant increase in hair growth and increased proliferation of hair matrix keratinocytes ex vivo was observed. We identified six proteins enriched in KSC-CM. A growth-factor cocktail that contains these six recombinant growth factors significantly increased the proliferation of HFDPCs and ORS cells and enhanced the hair growth of mouse models. Conclusion: These results collectively indicate that KSC-CM has the potential to increase hair growth via the proliferative capacity of HFDPCs and ORS cells.