Spain is one of the countries with a very high incidence of hydatidosis in the childhood. It represents 16.8% of all cases intervened for thoracic surgery for hydatidosis cysts in our department during the last ten years with a total of 21 children (inferior to 14 years) operated due to hydatidosis. Cough and pain were the symptoms more frequently encountered. The ratio unruptured/ruptured cysts was 3/1, higher than in the adults, with an average of 2.62 cysts per patient. Specific immunoglobulin E and histamine liberation test were the most useful tests in the laboratory. The usual surgical technique was a cystopericystectomy with total extirpation of the parasite of its rests. No recurrence was found in the follow-up of our patients.