Recent innovations in multidetector 3D CT have improved the spatial and temporal resolution of cardiac computed tomography (CT), which results in greater frequency of mass lesion identification and provides a new opportunity for more precise characterization. Although cardiac masses are rare entities, patients with cardiac masses may present with acute symptoms and may be encountered by emergency radiologists. The objectives of this article are to review the CT appearance of cardiac masses and the role of volumetric MDCT with 3D rendering to define characteristic features and provide a practical approach to formulating a differential diagnosis.