In a new case of chagasic placentitis in the Triângulo Mineiro, we have observed, through optical microscopy, the parasitism of miocytes of the vascular walls, a fact that was no previously described in literature. The electron microscopic study revealed: HI plentiful amastigotes of Trypanosoma cruzl in Hofbauer cells; (2) fibroblastic and collagen proliferation on the walls of small arteries and arterioles, occluding, at times, the lumen; (3) parasites in degenerated muscular cells and fibroblasts of the vascular walls. This is the first report of human chagasic placentitis with ultrastructural analysis.