We first review some concepts related to the Intra cardiac tumors that affect the pediatric patient, making emphasis in the rhabdomyoma, the most frequent congenital tumor of the heart. We then describe the case of a newborn girl in whom, by means of a fetal echocardiography, an early diagnosis of Intra cardiac mass had been mode; she was referred to our hospital, where, after completing the studies, surgery was performed; the anatomopathological diagnosis was rhabdomyoma. Her post operatory outcome has been very favorable, and her history suites as an example to emphazise the importance and usefulness of echocardiography In the early diagnosis of congenital cardiac defects that are initially asymptomatic and that, in the moment in which they manifest, they do so producing serious complications, including death.