Pulmonary sequestration is a rare congenital anomaly characterized by nonfunctioning embryonic pulmonary tissue that has no communication with the normal tracheobronchial tree. Pulmonary sequestration comprises 0.15% to 6.4% of all congenital pulmonary malformations and is divided into intralobar and extralobar types. The extralobar sequestration is rare, and comprises only 25% of all sequestrations. It is frequently associated with diaphragmatic hernia, eventration and other congenital anomalies. The authors report a case of extralobar retroperitoneal pulmonary sequestration which presented as adrenal tumour. The diagnosis was done by anatomo-pathological examination and no associated malformation was detected.