Data concerning operative treatment of 227 patients with lithiasis of the extrahepatic biliary ducts, covering an eleven-year period (1985 to 1995 inclusive), are presented. In all cases diagnosis and operation are done in the Second Surgical Clinic at the Medical University--State University Hospital "Alexandrovska"--Sofia. By type the surgical interventions are distributed as follows: external drainage of hepaticocholedochus--122 cases (53.74 per cent), choledochoduodenostomy 69 (30.39 per cent) and transduodenal papillosphincterotomy 36 (15.85 per cent). Fifteen patients develop postoperative complications (6.60 per cent), and in five patients the outcome is fatal with postoperative lethality amounting to 2.20 per cent. The basic indications for the various types of surgical interventions are established.