Neurocognitive compromise, a common sequela of HIV infection, ranges in severity from minor motor and information-processing speed decrements to severely incapacitating symptoms that affect functional independence. However, with the emergence of highly active antiretroviral therapy (HAART), neurocognitive phenotypes have become highly heterogeneous and increasingly fail to resemble pre-HAART presentations. This article provides an overview of our current knowledge of HIV-associated neuropsychological abnormalities, with an emphasis on the most recent attempts to classify cognitive impairment within Western and developing societies, the emergence of diverse cognitive presentations in the post-HAART era, factors that moderate the development or impact of HIV-related neurocognitive and functional deficits, and the neurophysiologic consequences of infection.