Background and Study Aims: Percutaneous access to the biliary tract is an important diagnostic and therapeutic tool in the management of biliary diseases. It is usually chosen when the endoscopic approach via endoscopic retrograde cholangiopancreatography (ERCP) fails, or is not possible. Once established, the percutaneous tract is then used for the treatment of biliary stones and strictures. To establish a percutaneous tract with a caliber large enough for cholangioscopy to be performed, or for a large-bore permanent drainage tube to be inserted, stepwise dilation up to 14 Fr or 16 Fr is usually required. We present here a new method of rapid dilation using specially designed materials, including a stiffenable guide wire and specially adapted bougies. Patients and Methods: Consecutive patients undergoing percutaneous drainage for biliary diseases were included in this prospective study, over a 19-month period. After establishment of a 10-Fr transpapillary drain, the patients were randomly assigned to either conventional percutaneous transhepatic biliary drainage (PTBD) or stepwise dilation using the new method, aiming at a need for only one further session, using a specially designed stiffenable metal guide wire of 6.6 Fr and plastic bougies. The details of the procedure (duration, materials used, technical ease), initial and later complications, assessment by the patients, and procedural costs were compared between the two groups. Results: Of the 60 patients included, 29 were randomly assigned to group I (the new method) and 31 to group II (the conventional approach); there were no significant differences between the two groups in terms of clinical data or biliary pathology. The clinical efficacy of PTBD was similar in the two groups, although three patients in group II were switched to the new procedure because of failure of dilation using the conventional approach. The rates of major complications (four of 29 in group I, five of 31 in group II) and patient tolerance were also similar. However, the new procedure led to a significant reduction in the cumulative procedure duration (20.1 minutes vs 30.1 minutes), mean number of sessions (1.1 vs. 1.7), and mean number of hospital days (2.0 vs 5.5), and was therefore also cost-effective, reducing costs from a mean of 5 813 to 2 581 German marks (DM) per patient. Conclusions: The new system for rapid establishment of large-caliber PTBD offers significant advantages in terms of saving hospital resources while maintaining clinical efficacy.