The human immunodeficiency virus (HIV) is a neurotropic retrovirus capable of producing a wide spectrum of central nervous system changes. Nearly 40% of HIV-infected patients demonstrate neuropathy ranging from dementia to the opportunistic infections and neoplasia seen in the acquired immunodeficiency syndrome (AIDS). Dramatic increases in the numbers of AIDS cases have allowed for the cytotechnologist and cytopathologist to become acquainted with the various pathologic manifestations of HIV infection. In this review, we are reporting the HIV-related diseases in the central nervous system and the role of diagnostic cytology.