Abstract: Objective To establish whether mesenchymal stem cells (MSC) exist in classic renal angiomyolipoma (RAML) tissue. Methods RAML tissue samples were taken from 8 patients during surgery, washed in PBS, hydrolyzed in collagenase, and incubated in adherent and passage culture. Their phenotype, parallel in vitro osteogenesis, and fat tissue differentiation were detected by fow cytometry. Results MSC-characterized adherent cells, isolated from the RAML tissue samples, did not express the surface markers of blood cells or endothelial cells such as CD14, CD31, CD34, CD45, and CD144, but expressed the surface markers of MSC such as CD29, CD44, CD73, CD90, and CD105, and could differentiate into osteogenic and fat tissue after incubated in vitro. Conclusion There exist a group of cells with morphology phenotype and features of MSC, and MSC are closely related with the development of RAML.