The authors report the cases of two young adults (25 and 27 years) presenting with congenital left ventricular aneurysm or diverticulum with healthy coronary arteries. This saccular evagination of the ventricular wall is rare. The authors describe a classification distinguishing muscular (contractile) diverticula, composed of the three cardiac tunics, fibrous diverticula and finally aneurysms with a dyskinetic wall. Although the limits of this classification are sometimes poorly defined, it presents a prognostic value, because it appears logical to propose nonsurgical management in the context of muscular diverticula and it seems legitimate to operate on fibrous diverticula and aneurysms due to the risks of rupture, extension, thrombosis or arrhythmia.