HIV-associated neurocognitive disorders (HAND) are one of major comorbidities in patients with HIV-1 infection. There are currently no standardized tests for screening HAND in such patients. The sensitivity of the cognitive function tests routinely used in clinical practice, such as the Mini-Mental State Examination and the Revised Hasegawa's Dementia Scale, is inadequate to rule out HAND, even in patients with clear abnormal behavior. We report a 41-year-old man with HIV-associated dementia, the most severe form of HAND, in whom the simplified methods did not show abnormal results, and a comprehensive battery of neuropsychological tests which covering several cognitive domains was needed to detect cognitive impairment.