Abstract: A method for the mass proliferation of urine-derived multipotent cells and a medium composition for the mass proliferation of urine-derived multipotent cells according to the present invention can be used to massively proliferate urine cells by efficiently isolating the same even from urine that has been left alone for a long period of time, and can be used to produce multipotent cells having characteristics of epithelial cells, mesenchymal cells, and stem cells.