Coronary angiography, left ventriculography, and magnetic resonance imaging (MRI) indicated that a 45-year-old male with a left ventricular intramyocardial tumor had adult type rhabdomyoma. The tumor was in the lateral wall of the left ventricle, making catheter biopsy unfeasible. Because the undeveloped tumor does not project into the cavity of his left ventricle, the patient had no symptoms. Angiography and MRI are beneficial in diagnosing intramyocardial tumors which other methods do not confirm.