Congenital pericardial defect is relatively rare and two different types, partial and complete, of different clinical significance have been recognized. Most reported defects are complete type and left-sided lesion. Most patients are asymptomatic or complain of vague chest pain. Partial pericardial defect can be potentially fatal due to cardiac herniation and strangulation or coronary insufficiency. Plain chest reontgenography shows abnormal prominence along the cardiac border. 2-D echocardiography demonstrates a drop-off of pericardial echo and protruding cardiac chamber through the defect. Because of the potential fatality, surgical repair is recommended for the partial pericardial defect. We report a case of congenital partial left pericardial defect, which was diagnosed by plain chest reontgenography and 2-D echocardiography, with related literatures.