A group of 152 patients who underwent surgery for liver hydatid disease from 1982 to 1992 was studied. In all cases, the cysts were evacuated, part of the cyst wall was excised and the cavity edges were hemostatically sewn over. The residual cavity was obliterated and drained. Eight of these patients (5.2%) developed external biliary fistulas. In 2 cases the fistula stopped draining within 40 days. Six patients required reoperation due to septic complications (2 cases), long-standing high output fistula (1 case), obstructive jaundice (1 case) and a wide cavity-biliary tree communication (2 cases). At reoperation in all cases, suture of the communication between the residual cavity and the biliary tree was performed with further obliteration and drainage of the residual cavity. In 3 cases the common bile duct was explored, and in 1 patient a choledochoduodenostomy was performed. Four fistulas stopped draining in 4-6 weeks and two 10-16 weeks postoperatively. We conclude that in patients with large calcified hydatid cysts of the liver, partial capsectomy and suture of the communication between the residual cavity and biliary tree are essential steps to avoid biliary-cutaneous fistula formation. The initial treatment of biliary-cutaneous fistula is conservative but, if the fistula persists, stent insertion or endoscopic sphincterotomy is indicated. Should this fail, reoperation is unavoidable.