Most retroperitoneal tumors such as renal cell carcinoma have been associated with tumor thrombus extending into the renal vein, inferior vena cava (IVC), and heart. The retroperitoneal metastatic potential of testicular tumors is well known. We report here the first instance of a cardiac murmur prompting diagnosis of metastatic testicular neoplasia in an 18-year-old patient. Chemotherapy was delayed and after successful surgical resection of the ventricular mass, the patient recovered uneventfully. This case underscores the need to pursue abnormal cardiac exams in newly diagnosed testicular cancer patients.