In a 70-year-old man who had angina, exercise-induced ventricular tachycardia, and presyncopal symptoms, transthoracic and transesophageal echocardiography disclosed a large atrial mass that resembled a myxoma. Subsequent evaluation by magnetic resonance imaging identified the mass as an intracardiac lipoma attached to the posterior wall of the right atrium, a diagnosis that was confirmed by surgical intervention. Thus, the diagnostic utility of magnetic resonance imaging as an adjunct to echocardiographic evaluation of intracardiac masses was demonstrated.