A serological survey was carried out to determine the prevalence of Chagas' disease in municipality. The following variables were analyzed to identify the form of transmission of this disease: age, sex, clinical and transfusional history, degree of kinship and serology. Within the 863 municipalities we studied, we identified 265 individuals, with serology testing done on them and on their respective mothers. Of these, 232 tested negative serology for Chagas'disease and 33 (14.2%) positive. We found 9 (3.9%) patients, of 14.3 years. average age with vectorial transmission and 24 (10.3%), of 26.6 years. average age with probable, vertical and vectorial transmission. When we compare the two groups in regard to age averages and manner of transmission of Trypanosoma cruzi, we encounter a statistical significance. Our results suggest the existence of an active, vectorial transmission of Trypanosoma cruzi in Mulungu do Morro.