The aim of the study was to review the clinical characteristics of operated patients with respect to pulmonary sequestration and analyze diagnostic and therapeutic problems connected with this anomaly.Material and methods. We performed a retrospective analysis of 23 patients operated on because of pulmonary sequestration between 1963 and 2004 in the Departments of Thoracic Surgery in Zakopane (10 patients) and Szczecin-Zdunowo (13 patients).Results. The study group comprised 8 men and 15 women and the mean age was 28 years. 15 patients (65.2%) presented with clinical symptoms such as coughing, fever and chest pain. Preoperatively, pulmonary sequestration was suspected in 5 patients. Amongst the remaining patients, the preoperative diagnosis was lung cancer (9 patients), metastasis from testicular neoplasms (n=1), emphysematous bullae (n=2), pulmonary cyst (n=4), bronchiectasis (n=1) and lung abscess (n=1). None of the patients were subjected to arteriography and 6 patients underwent contrast-enhanced computer tomography examination, although it did not lead to a proper diagnosis. We found 20 intralobar sequestrations and 3 extralobar sequestrations, which were situated above the diaphragm. There were 11 sequestrations on the right side and 12 on the left side. The operations performed included: lobectomy (14 patients), segmentectomy 1+2 (n=1), wedge resection (n=3), sequestrectomy (n=3), lower bilobectomy (n=1), and middle lobectomy (n=1). Blood supply from the thoracic aorta was found in 17 patients and the abdominal aorta in the remaining 6 patients. In 5 patients, the pulmonary sequestration was supplied by more than one artery. Complications included hemorrhage from supplying arteries in 8 patients and phrenic nerve palsy in one patient. One patient required mechanical ventilation after the operation. There was no further morbidity and mortality. Distant surgical results were good.Conclusions. 1. Pulmonary sequestration in adults is difficult to diagnose before the operation, even with a detailed computer tomography examination. 2. Intralobar sequestration is much more common (87%) than extralobar and is often situated in the basal segments with comparable incidence on the right and left sides. 3. The greatest danger during the operation is major bleeding from the supplying artery. 4. Prognosis after the operation is favorable.