Hydatidosis is a zoonosis of worldwide distribution caused by the parasite Echinococcus granulosus. Clinical manifestations include cyst formation, most commonly in the liver (67-89%) and lungs (10-15%). Renal localizations are rare. We report a case of renal hydatidosis in a five-year-old child treated in a tertiary pediatric hospital in Argentina. After the diagnosis was made, elective surgery was performed, which led to a rapid recovery. Copyright © 2013 by The American Society of Tropical Medicine and Hygiene.