Eight patients with surgically proven primary intrapericardial masses were evaluated over the past 3 years using a variety of radiologic tests. Dynamic CT prospectively identified the masses in all eight patients, esophagography was positive in four of five patients, chest radiography was prospectively positive in one of eight patients, and echocardiography identified a mass in only one of seven patients. Furthermore, precise CT localization of the masses proved important in surgical management of these patients, suggesting in several instances the need for cardiopulmonary bypass. Although echocardiography is the modality of choice in evaluating potential pericardial effusion, CT should be the preferred diagnostic test for suspected intrapericardial mass lesions.