The study of peripheral nerve function in development and disease can be facilitated by the availability of cultured cells that faithfully mimic in vivo Schwann cell growth, maturation, and differentiation. We have developed a method to establish purified mouse Schwann cell culture from a single embryo at embryonic day 12.5 (E12.5) to define the abnormalities in Schwann cells caused by loss of the neurofibromatosis type 1 (Nf1) tumor suppressor protein, the RAS-GAP neurofibromin. Our method generates 2-3 x 10(6) cells/embryo highly purified (>99.5%) mouse Schwann cells in less than 2 weeks from a single E12.5 mouse embryo. Manipulation of cell medium allows purification of a Schwann-like cell population, termed Nf1-/-TXF, that resembles a tumorigenic cell in that it grows dissociated from axons and grows rapidly, yet retains expression of Schwann cell markers. We describe the preparation and characterization of both cell types.