From January 1st up to September 30th 1990, 77 patients with leptospirosis were admitted at the Infectious and Parasitic Diseases Service of the Hospital das Clínicas of the Universidade Federal de Pernambuco. The majority (64) were male patients, and average age was 28 years old. Serovars icterohaemorrhagic and canicola were the most frequent. CSF examination was performed in 67 (87.0%) patients and it was abnormal in 64 (95.52%). Micro-agglutination test for leptospirosis with live antigens was performed in CSF, as well as immunological tests for syphilis, cysticercosis and schistosomiasis for differential diagnosis. Concerning the serovar identification, results of microagglutination test for leptospirosis in CSF were significant considering the similitude of responses when compared to those found for blood samples.