A retrospective study of 9 cases of extra-hepatic biliary cyst is presented. Prior to admission to our hospital, 5 patients had been operated upon elsewhere. This initial operation proved to be of great importance. In 4 patients initial excision of the cyst was performed resulting in complete regression of symptoms, and no further surgery was required. In 5 patients the cyst was not excised initially and cysto-enterostomy was performed. Recurrence of symptoms and complaints, with major morbidity, occurred in all but one of these patients. After several operations, only final excision of the cyst definitively suppressed the symptoms, but in one patient the cyst could no longer be excised. Cysto-enterostomy results in recurrent symptoms and cholangitis and should be avoided. Early excision of extra-hepatic biliary cysts should be performed whenever technically feasible, not only to prevent these complications but also because of the risk of malignant degeneration related to the cyst.