Neurofibromatosis 1 is one of the most common autosomal dominant disorders affecting the nervous system. Individuals with neurofibromatosis 1 present with abnormalities of both astrocytes and neurons that result from reduced or absent expression of the NF1 gene product neurofibromin. Impaired neurofibromin function in these nervous system cells contributes to the development of astrocytomas, learning disabilities, and radiographic abnormalities of the brain. With the identification of NF1, significant advances have begun to unlock some of the mysteries that surround the molecular pathogenesis of neurofibromatosis 1-associated brain abnormalities. With continued advances in our basic understanding of NF1 function, future targeted therapies for neurofibromatosis 1-associated central nervous system abnormalities can be developed.