The precursor cells of oligodendrocytes, the myelin-forming cells of the central nervous system, were first discovered in 1993 by Raff, Miller, and Noble. They have been extensively studied and are referred to in the literature as either oligodendrocyte-type-2 astrocyte progenitor cells or oligodendrocyte precursor cells (OPC). The developing and adult central nervous system both contain OPC. In culture, OPC can be generated from neural progenitors or neural stem cells by the stimulation of basic fibroblast growth factor. OPC proliferate in the presence of platelet-derived growth factor or factors produced by astrocytes, and differentiate into mature oligodendrocytes. Based on these qualities, OPC provide an exceptional model to study developmental transitions. ROPC are isolated from postnatal day 2 CD(SD) IGS Rat brain. ROPC are cryopreserved after purification and delivered frozen. ROPC are characterized by immunofluorescence with antibodies specific to A2B5 and O1. ROPC are negative for mycoplasma, bacteria, yeast, and fungi. ROPC are guaranteed to further culture under the conditions provided by Creative Bioarray; however, ROPC are not recommended for expanding or long-term cultures due to limited expansion capacity.