Extensive calcification of the heart, involving predominantly the right ventricle and interventricular septum, was observed in a 3-h-old baby. The aetiology of the condition was attributed to infection by toxoplasma gondii, based on the presence of several visceral lesions allied to the identification of the microorganism. The case is reported in view of the rarity of the type lesion. It is considered that calcification of the myocardium is secondary to vascular, inflamatory or toxic condition. The factors implicated in the pathogenesis of this unusual myocardial lesion are discussed.