We report the use of cardiac magnetic resonance imaging in the diagnosis of a large right atrial vegetation. A 44-year-old woman admitted with septic shock was found to have a giant mass attached to the lateral free wall of the right atrium that was consistent with tumor on transesophageal echocardiography. Interestingly, diagnosis of vegetation was later made by cardiac magnetic resonance imaging and confirmed by surgical pathology. The case highlights not only an atypical presentation for intracardiac vegetation, but also the use of cardiac magnetic resonance imaging as an adjunct to transesophageal echocardiography in the evaluation of cardiac masses.