The most important imunobiological aspects of neurocysticercosis and the cerebrospinal fluid (CSF) syndrome in this disease are reviewed. A study was made of 1.577 samples of CSF from 1.282 patients who suffered from several diseases of central nervous system. They were divided in 3 groups: 1- 459 patients with normal results of CSF tests; 2- 600 patients with pathological CSF, but with immunological reactions non-reactive: 3- 233 patients divided in 8 sub-groups according the results of the immunological reactions. CSF immunofluorescent reactions for syphilis (FTA-Abs). cysticercosis and toxoplasmosis were analysed. Results obtained showed that immunofluorescent reaction for cysticercosis has the same sensivity and especificity as the complement fixation test, but, no< considering those samples who showed delay in hemolisys of the complement fixation test, the immunofluorescent reaction showed significative, better results, as occurs, with the FTA-Abs in syphilis. The agreement between the results of the immunofluorescent reaction and complement fixation in CSF contributes for a better security to the imunodiagnosis of cysticercosis and is particulary useful in those cases in which the complement fixation test in anti-complementary. The positive of immunofluorescent reaction for cysticercosis in CSF must be incorporated to the CSF syndrome of the disease and contributes to the immunobiological studies of the disease.