The lecture intended for general practitioners represents collated information on the most important mechanisms of brain damage under HIV infection, the rate of neurocognitive disorders and their role in disability of patients, classification of these disorders. The capabilities and importance of diagnosis and an in-depth work-up of patients for establishing complete clinical diagnosis and order of effective treatment are presented in the lecture. Much attention is given to immunosuppression influence, brain cell elements involvement and forming of reservoir of HIV infection in pathogenesis of neurocognitive diseases. The lecture describes special aspects of radiology examinations including magnetic resonance imaging, magnetic resonance spectroscopy for assessment of metabolism and tissue perfusion using some chemical markers. Approaches to prevention, diagnosis and treatment are provided taking into account the stage of a disease. An algorithm of detection of causes and diagnosis of cog- nitive disorders is stated in the lecture and the role of different diagnostic approaches at different stages of HIV infection including HIV-associated diseases is shown.