A comparative study was conducted on membrane (M) and vesicular fluid (VF) from cysticerci of Taenia solium (Tso) obtained from naturally infected swine and the Taenia crassiceps ORF strain (Tc) maintained by experimental infection of female BALB/c mice. The study was carried out using immunoblotting to detect antibodies in cerebrospinal fluid (CSF) from patients with neurocysticercosis. No reactivity was observed in the 32 samples from a control group. Of the 23 CSF fluid samples from patients with neurocysticercosis, 22 (95.6%) were reactive in the M-Tso blot and 21 (91.3%) were reactive in the other three blots (VF-Tso, M-Tc, and VF-Tc). Immunodominant peptides in each antigen were 98-92 kD, 56-52 kD, and 72-68 kD in M-Tso; 72-68 kD, 120 kD, 155 kD, 98-94 kD, 76 kD, and 115-108 kD in VF-Tso: 72 kD, 62 kD, and 42 kD in M-Tc; and 72-68 kD and 95-92 kD in VF-Tc. The cross-reactivity observed in the immunoblots performed on CSF samples from patients with neurocysticercosis indicates that the parasites share important epitopes present at sufficient concentrations for use in immunologic tests.