Cardiac lymphoma is becoming increasingly frequent, especially in the context of acquired immune deficiency syndrome, and due to progress in imaging, particularly echocardiography. The authors report the case of a 49-year-old patient in whom the diagnosis of cardiac lymphoma was established in the presence of complete atrioventricular block, tamponade and right atrial tumour. The authors review the various electrocardiographic and echocardiographic features of cardiac lymphoma.