Abstract: A serum-free or serum-depleted medium for the short- and long-term proliferation and development of cells, particularly hematopoietic cells and bone marrow stromal cells, the medium comprising cell proliferation and development effective amounts of:a standard culture medium such as Iscove's modified Dulbecco's medium; serum albumin; transferrin; a source of lipids and fatty acids; cholesterol; a reducing agent; pyruvate; a glucocorticoid (when the cells to be cultured are hematopoietic cells); nucleosides for synthesis of DNA and RNA; growth factors that stimulate the proliferation and development of stromal cells and cells from a variety of tissues or organs, such as epidermal growth factor, fibroblast growth factor, platelet derived growth factor, and insulin; and extracellular matrix materials, such as collagen, fibronectin, and laminin.