Objective To observe the possibility of inducing mesenchymal stem cells(MSCs)to differetiate into hair follicle stem cells by the supernatant of cultured hair follicle EM>in vitro/EM> and to investigate the transdifferentiation potentiality of MSCs. Methods MSCs were isolated and cultured from rat bone marrow by complete adherence. MSCs of passage 3 were characterized with markers CD44 and CD29 by immuohistochemical staining technique. The stem cells were induced by the supernatant of cultured hair follicle. The morphological character was observed by inverse phasecontrast microscopy. The expression of keratin 15 was detected by immunohistochemical staining technique and immunofluorescence staining technique. RT-PCR was further used to detect the expression of keratin 15. Results The isolated and separated MSCs were immunostaining positive in CD44 and CD29. After induced by the hair follicle conditioned medium EM>in vitro/EM>, MSCS could be partially identified by the positive staining for keratin 15, a specific antibody of hair follicle stem cells. After 3 weeks′ induction, keratin 15 was detected by RT-PCR in MSCs induced by supernatant of cultured hair follicle. Conclusion MSCs have the potential to differ