The object of the present paper is to show four patients treated at the "Ricardo Gutiérrez" Children's Hospital, with diagnosis of complicated liver hydatid disease, since april 1977 until january 1997. The four patients were previously healthy, and were admitted with acute symptomatology, which varied depending on the kind of complication. They were all studied before surgery, except for one patient, with simple x-ray, abdominal ultrasonography, and in some cases with computerized tomography; in addition blood serologic analysis were performed, which allowed us 100% effectiveness in the diagnosis. The observed complications were two intrabiliary rupture of the hydatid cyst, one infection of the cyst, and one intra abdominal rupture. All patients underwent surgery, which confirmed the diagnosis, and an uneventful follow up of 20 years in the first child. In spite of the infrequent presentation of the complicated hydatid disease, in an endemic region it is not impossible for it to be seen. In this case it will require a well trained team of specialists, to solve not only the problems that the diagnosis and treatment mean, but also the possibility of a correct follow-up, with the resolution of the possible obstacle that might show-up for the disease itself, and from the changes that the surgery produces.