Human immunodeficiency virus-1 (HIV-1)-associated dementia is a severe neurological complication of HIV-1 infection that affects 15-20% of the patients in the late stages of acquired immunodeficiency syndrome. HIV-1-associated dementia is most probably a consequence of HIV-1 infection of the brain rather than of an opportunistic pathogen. The exact mechanism by which the virus causes this disorder, however, is not completely understood. A number of HIV-1 proteins have been shown to be released from HIV-1-infected cells and / or to be present in the extracellular milieu in the HIV-1-infected brain. Moreover, these proteins have been shown to posses neurotoxic and / or neuromodulatory features in vitro . This review describes the possible direct interactions of the HIV-1 proteins gp120, gp41, vpr, tat, rev, vpu and nef with neurons, which might play a role in the development of HIV-1-associated dementia in vivo .Keywords Acquired immunodeficiency, human immunodeficiency virus-1-associated dementia, human immunodeficiency virus-1 proteins, neurons, neurotoxicity.