Objectives: To compare the clinical features and the surgical approaches between single pulmonary (SPH) and hepatopulmonary hydatidosis (HPH). Methods: The hospital and follow-up records of 141 patients who had undergone surgery for pulmonary hydatidosis in our clinic between January 1991 and January 2001 were reviewed. Forty-nine patients (34.8%) had concomitant liver cysts in addition to the pulmonary cysts and they were regarded as HPH (Group I). The remaining 92 (65.2%) patients had SPH (Group II). Both groups were compared according to their clinical, radiological and surgical features. Results: Seventeen (34.7%) male and 32 (65.3%) female patients had HPH, The mean age of the patients with HPH was significantly higher than the age of those with SPH (P < 0.05) and the frequency of hepatopulmonary localization, which is contrary to single pulmonary cyst, was significantly higher in females (P < 0.05). The majority (67.3%) of the cysts located in the liver were solitary. Multiple pulmonary cysts were in higher ratio in Group II, compared to Group I (45.7 vs. 22.8%) and bilateral pulmonary cyst ratio was higher in Group II, as well (26.5 vs. 13%) (P < 0.05). In 14 patients (28.6%), the concomitant cysts localized in the dome of liver were extirpated via right thoracophrenotomy, and in one of them sternophrenotomy was performed. There was no statistically significant difference associated with the postoperative complications and hospital stay between groups. No recurrence and mortality were recorded in Group II. Conclusions: Multi-organ localizations (especially liver) should be examined in all patients with pulmonary hydatid cysts. HPH is more frequent in female patients over 40 years of age. The pulmonary cysts in HPH show a tendency to be bilateral and multiple. HPH should be regarded as a different entity since it can cause either economic or tabour loss due to the multi-operations and prolonged postoperative care. The operative strategy and approach should be different in hepatopulmonary cysts especially if they locate in the right or bilateral lung. One-session operation with the improvements of its techniques and methods should be considered in selected cases. (C) 2002 Elsevier Science B.V. All rights reserved.