In its early stages, HIV-1infection involves the Central Nervous System causing neuropsychological manifestations. With the aim of studying the cognitive functions in HIV-1-infected patients, a total of 20 patients infected with HIV-1 with CD4+ lymphocyte count >200 cells/mm³ were studied in accordance with the Wechsler AdultIntelligence Scale (WAIS-III). The present study comprised 20 patients, 5 (25 percent) male and 15 (75 percent) female, with a mean age of 39.65 and standard deviation of 10.15 years. The mean CD4+ lymphocyte count was 467.20 with a standard deviation of 215.45 cells/mm³. Amongst the 14 patientswho received highly active anti-retroviral therapy (HAART), we noted 1 case in which the performance of the cognitive functions, attention span and learning, was considered to be very low according to WAIS-III, and the remaining (n=13) patientswho were treated with HAART demonstrated a performance that was not considered to be outside of the WAIS-III mean. By using WAIS-III testing, it was possible to detect performance of the cognitive functions considered to be very low in HIV-1 infected individuals, even with those receiving HAART.