Specificity of antibodies in cerebrospinal fluid (CSF) of human cerebral gnathostomiasis cases were examined by indirect fluorescent antibody technique against paraffin sections of Gnathostoma spinigerum larva. Specific greenish fluorescence was observed at cuticle, esophagus, muscle cells, intestinal cell cytoplasm and microvilli. CSF of confirmed cerebral cysticercosis cases gave fluorescence mostly at the cuticle. It is suggested that parasite-specific antigen may be present on intestinal cell microvilli and CSF would be a good source of antibodies in studying specificity of antibodies to gnathostome infections.