While much of the current literature concurs that neuropsychological decline does not occur among gay men in the early stages of HIV infection, there is no comparable body of evidence with regard to seropositive intravenous drug users (IVDU). In this study, 45 seropositive (CDC groups 2, 3, and 4a) IVDU in recovery and 55 seronegative IVDU in recovery were given a complete battery of neuropsychological tests measuring attention, language, visual-motor, memory, and conceptual skills. The groups were not significantly different in age, incidence of childhood and adult head injury, types of drugs used, length of use of cocaine, crack, amphetamines and hallucinogens, overdose history, and length of time in recovery. In addition, groups were statistically corrected for education level and length of heroin use. Results indicate that the seropositive participants scored significantly lower on measures of divided attention, visual short-term memory, graphomotor speed and accuracy, auditory language shortterm memory and abstract concept formation. Further analyses revealed that 18% of participants with Persistent Generalized Lymphadenopathy (CDC group III) and 27% of those with constitutional disease (CDC group IVa) were neuropsychologically impaired, as their performance was two standard deviations or more below the normative mean on two or more measures. These results are similar to the reported performance of gay men with full-blown AIDS in a number of studies. It is hypothesized that because of premorbid neurological insult, the toxic effects of drug abuse on brain tissue, and the immunosuppressive effects of the drugs, subcortical brain cells of IVDU are more vulnerable to the invasion of HIV, and neurological deterioration may occur at earlier stages of HIV Spectrum Disease in IVDU than in gay men.