Congenital defects can be further characterized by location and whether there is a partial or complete absence of the pericardium. Complete left-sided defects are most common with a reported prevalence of 70% of all pericardial defects. Complete bilateral Absence of the pericardium accounts for 9%, and right-sided defects comprise 17% of all. • Thirty to fifty percent of patients with the congenital absence of the pericardium have associated congenital anomalies. • Atrial septal defects, patent ductus arteriosus, mitral valve disease, tetralogy of Fallot, and sinus venosus defects with PAPVD • Pericardial defects have also been seen in patients within aortic connective tissue disorders and characteristics suggestive of Marfan syndrome. Several cases of type an aortic dissection have been seen in patients with the absence of the pericardium. • Early atrophy of the left or right duct of Cuvier may lead to abnormal budding of the lung, resulting in bronchogenic cysts, sequestrated lungs, and aberrant lobes. Additional non-cardiac anomalies include pectus excavatum and diaphragmatic hernia. • Pericardial defects have also been noted in patients with VATER syndrome (vertebral defects, anal atresia, tracheoesophageal fistula, and radial and renal dysplasia). We present a case of absent left-sided pericardium and herniation of the heart through the defect and pleural effusion and pneumothorax causing tamponade. Urgent sternotomy and drainage improved the patients’ condition and he was discharged a week later. Absent pericardium rarely gives life-threatening complications but in our case, the pneumothorax developed during surgery led to herniation and compression of the heart and was dealt with urgent sternotomy.