During a 20-year period, 376 children with hydatid disease were treated at Hacettepe University Ihsan Dogramaci Children's Hospital. There were 223 males and 153 females with a mean age of 8.9 +/- 0.1 years. Hydatid cysts were localized in the lungs in 222 patients, in the liver in 56 patients, and in other organs in the remaining patients. Cough. fever, and abdominal pain were the most common symptoms. One hundred eight patients had medical, 182 patients had surgical, 73 patients had medical and surgical,and 4 patients had medical and percutaneous drainage treatment as the initial therapy.