The authors report eight cases of Chagas' heart disease, proved by positive Machado-Guerrero reaction, in whose evolution there occurred cerebrovascular accidents. They discuss the etiology of these accidents, excluding the common etiological factors and set forth the hypothesis of cerebral embolism from cardiac mural trombosis. Death occurred in four cases, which were submitted to post mortem examination; in two cases the necroscopic findings support the hypothesis. In one of the other two it was found mural thrombosis in the left ventricle and three cerebral hemorrhagic softenings, but there was simultaneously diffuse cerebral arteriosclerosis and in the other there was a cerebral softening and none of the habitual etiologic factors was found, but there was no thrombosis in the left heart; the possibility is reminded of a weakly adherent to endocardium mural thrombus, which loosed completely. The embolic nature of these cerebrovascular accidents is supported by the authors in the eight cases reported and they emphasize Chagas' disease as an etiological factor of cerebral embolism.