The Authors report two cases of chronic Chagas' heart disease. The children came from the States of São Paulo and Minas Gerais. The purposes of the report are to discuss the possibility of natural contamination in rural areas in those regions of the states from which the children came, and also to contribute to the knowledge of the Physiopathologic aspects of Chagas' heart disease. Both cases presented cardiac failure and did not respond to current therapeutic treatment and they died of uncontrolled cardiac failure. The Authors comment in a general way on the phisiopathology of the disease based on pertinent literature.