Cognitive event-related potentials (ERPs) were recorded in 33 HIV-positive individuals with clinical signs of dementia (group C) using an auditory oddball paradigm, in comparison to a healthy control group of comparable education and social environment (group A) and to a cohort of clinically asymptomatic HIV-positive individuals (group B). Parameters evaluated were: N1, P2, N2 and P3 latencies and N1-P2, P2-N2 and N2-P3 amplitudes. Results of group B and C were correlated with clinical findings, test psychometric performance and standard EEG records of both groups. The demented patients revealed significant prolongations of N2 and P3 peak latencies or complete abolition of these "endogenous," not stimulus-related, ERP peaks. Clinical bradykinetic symptoms and time-dependent psychometric abilities correlated with N2 and P3 latency prolongations and with the general slowing of the alpha rhythm, indicating an involvement of cortical and subcortical structures in HIV-related brain disease.