Neurocognitive impairment (NCI) occurs in 10 - 60% of people living with HIV/AIDS (PLWHA), depending on the severity of the NCI and the stage of the disease. The clinical features and definitions have evolved over the past two decades. HIV-associated neurocognitive disorder (HAND) is a new term used to describe the spectrum of neurocognitive impairment seen in HIV/AIDS. The earliest to most advanced stages are asymptomatic neurocognitive impairment (ANI), minor neurocognitive disorder (MND) and HIV dementia (HAD), respectively. People with HAND have impairment on multiple cognitive domains, including attention, concentration, memory, executive function, motor functioning and speed of information processing, and sensory perceptual/motor skills deficits. The milder forms of HAND are easily missed. Diagnosis can be made on clinical grounds in the most severe cases; however, milder forms and confirmation of the diagnosis require neuropsychological testing. Screening tests have limited utility, especially in the milder forms of HAND. Individual subtests derived from longer neuropsychological batteries may be complementary in the diagnosis of HAND. Highly active antiretroviral therapy (HAART) has led to a 40% decline in the incidence of HAD. In the post-HAART era, HAD runs a more chronic course, is milder and is reversed in about a third of cases. However, HAART is not universally successful because incident cases occur in people on HAART. Overall HAART has been shown to be of benefit, and screening for HAND should be the standard of care for PLWHA. HAD is an AIDS-defining illness and patients qualify for HAART irrespective of their CD4 count. However, the benefit of starting ARVs for people with ANI and MND is currently inconclusive.