Vasculitis refers to heterogeneous clinicopathologic disorders that share the histopathology of inflammation of blood vessels. When unrecognized and therefore untreated, vasculitis of the nervous system leads to pervasive injury and disability making this a disorder of paramount importance to all clinicians.Remarkable progress has been made in the pathogenesis, diagnosis, and treatment of vasculitis of the central (CNS) and peripheral nervous system (PNS). The classification of vasculitis affecting the nervous system includes (1) Systemic vasculitis disorders (necrotizing arteritis of the polyarteritis type, hypersensitivity vasculitis, systemic granulomatous vasculitis, giant cell arteritis, diverse connective tissue disorders; viral, spirochete, fungal, and retroviral infection; (2) Paraneoplastic disorders; (3) Amphetamine abuse; (4) Granulomatous angiitis of the brain; (5) Isolated peripheral nerve vasculitis, each in the absence of systemic involvement; and (6) diabetes mellitus, associated wtih inflammatory PNS vasculopathy.Vasculitis is diagnosed with assurance after intensive evaluation. Successful treatment follows ascertainment of the specific vasculitic disorder and the underlying cytochemical mechanism of pathogenesis. Clinicians must choose from among the available immunomodulating, immunosuppressive, and targeted immunotherapies, unfortunately without the benefit of prospective clinical trials, tempered by the recognition of all of the possible medication related side effects.