In the 1990s, HIV has replaced syphilis as the "great masquerader." Virtually every level of the neuraxis may be affected in a patient with HIV infection. The superimposition of multiple levels of neuropathology further complicate the bedside neurologic diagnosis of an AIDS patient. This article has reviewed the variety of forms of peripheral neuropathy that may be associated with HIV infection and its treatment. Distal symmetrical polyneuropathy may be produced in patients with HIV infection by neurotoxic drugs (e.g., vincristine, INH, ddC, or ddI) or by vitamin B12 deficiency or may develop in the later stages of HIV infection without identifiable cause. GBS and CIDP occur with increased frequency in early HIV infection owing to presumed autoimmunity, and these IDPs respond to plasmapheresis or prednisone, similar to HIV-seronegative patients. A limited distribution of mononeuropathy simplex or multiplex occurs in patients with CD4 counts greater than 200; the neuropathy will usually spontaneously improve in these patients. Widespread mononeuropathy multiplex may occur in patients with AIDS and CD4 counts less than 50 and is then usually caused by CMV infections; those neuropathies are usually progressive unless antiviral treatment is given. Progressive polyradiculopathy usually occurs in patients with AIDS and low CD4 counts. If the cerebrospinal fluid has a polymorphonuclear pleocytosis, CMV infection is almost always present, and progression is expected unless ganciclovir therapy is promptly started. Finally, mild autonomic neuropathy is commonly present in HIV-infected patients. Protocols for the evaluation and therapy of cranial and peripheral neuropathies are presented (Figs. 6 and 7). It is unfortunate but likely that increasing numbers of "neuro-AIDS" patients will be encountered, not only in urban medical centers but also in general community practice. The pace at which research in the field of HIV research has proceeded is unprecedented. It is, therefore, important that neurologists stay at the forefront of investigation and clinical care of these complex disorders.