A case of fatal cardiac larva migrans in a 10-year-old boy is described. The autopsy findings were quite dramatic, with a bosselated, sessile polypoid mass involving the left ventricular myocardium and protruding into the ventricular lumen. The precise morphologic characterization of the zoonotic ascarid larva was impaired by advanced resorption of the larva by an inflammatory infiltrate. Nonetheless, morphometry of the larval remnants strongly suggested the raccoon ascarid, Baylisascaris procyonis, as the causative agent.