The frequency of encephalic parasitism in mice experimentally inoculated with different T. cruzi strains has been studied by examining semi-serial histological sections. Parasites have been found in 1.6-2.2% of the examined sections from animais inoculated with ctrains FL, MR, Y, Berenice, and in 20.5% of those inozulated with PNM strain. Those results have been suggested to be caused by different tropism of the parasite to the central nervous system. The importance of experimental models suitable to be used in the study of encephalic lesions in Chagas disease has been discussed.