Soluble extracts of Y, São Felipe and Colombian strains of Trypanosoma cruzi were analyzed against their homologous and heterologous antisera by crossed immunoelectrophoresis and crossed immunoelectrophoresis with intermediate gel. In the homologous system, the results showed 35 precipitin lines for Y strain (32 anodic, 3 cathodic), 24 precipitin lines for SãoFelipe strain and 22 for Colombian strain. No cathodic antigen was observed for these last two strains which were consequently considered particular to Y strain. Using crossed immunoelectrophoresis with intermediate gel, 5 antigens particular to Y were shown when reacted against anti-são Felipe strain and 8 when reacted against anti-Colombian strain. São Felipe strains had one particular antigen when reacted against anti-colombian strain whereas none was observed when reacted against anti-Y strain. Finally Colombian strain did not show any particular antigen in reaction with anti-Y or anti-São Felipe strains. These results indicate that strains belonging to different types (morphobiological and histopathological characters) also demonstrate important antigenic differences.