Congenital absence of pericardium is a rare malformation. We report 2 young patients with a diagnosis of congenital absence of the pericardium. The posteroanterior view of the chest X-ray showed displacement of the left cardiac border into the left hemithorax. Unusual acoustical windows and abnormal cardiac and septal motion during echocardiography suggested the diagnosis of congenital absence of pericardium. Magnetic resonance imaging definitive confirmed diagnosis of congenital absence of pericardium.