Primary cardiac tumors are infrequent and usually benign. They can manifest as dyspnea, chest pain, palpitations, sudden death, peripheral embolism, cyanosis, or general symptoms. They are sometimes an incidental finding in an asymptomatic patient. We describe a 33-year-old man who was seen because of dyspnea and palpitations. Transthoracic echocardiography revealed, on the lateral wall of the left ventricle, an intramyocardial mass that was successfully resected surgically. The pathologic diagnosis was hamartoma of mature cardiac myocytes. We discuss the usefulness of imaging techniques for identifying cardiac masses.