Until now only few data have been published regarding the role of computed tomography for the detection of coronary thrombosis in coronary artery ectasias. We report the case of a 49-year-old man who was admitted to our hospital for prolonged chest pain followed by syncope. An early coronary angiography, performed after electrocardiography, the evaluation of cardiac enzymes and echocardiography, was carried out and revealed a diffuse coronary artery ectasia, involving particularly the right coronary artery. In addition, the following day the patient underwent contrast-enhanced cardiac 64-slice computed tomography, which revealed the presence of an intraluminal thrombus in the distal tract of the right coronary artery. Therefore, he was put on anticoagulant therapy and was discharged 2 days later. In conclusion, in this case, computed tomography played an additional and complementary role to coronary angiography.