In a seven year time period (July 1984 to June 1991) were studied CSF samples of 36,216 new patients, 470 of them infected by HIV. Number of AIDS patients represents 1.30% of total cases examined in the laboratory during this time period. Normal CSF was observed in only 16 cases (3.4%). Associated pathologies occurred in 66% of cases. Opportunistic infections predominated among them (227 cases). Data support indication for CSF examination in HIV infected patients. This exam must be as complete as possible.