ELISA detection of specific antibodies in the serum (IgG) and cerebrospinal fluid (IgG, IgM and IgA) was evaluated in 28 patients. Diagnosis of cerebral cysticercosis and evaluation of disease activity was based on CT scan findings. Specific IgG antibodies were found in the serum in 83.3% of patients with active disease and 10% of those with inactive disease. Cerebrospinal fluid tests evidenced specific antibodies in all patients with active disease and none of the patients with inactive disease. The specific CSF antibodies were IgG (94.4%), IgM (66.6%) or IgA (66.6%). Antibody titers were significantly higher in patients with an intraventricular vesicle or cyst.