Endoscopic retrograde cholangiopancreatography (ERCP) is playing an increasingly important role in the evaluation and treatment of children with disorders of the pancreas and biliary tree. In this article the technique, indications, and complications of diagnostic and therapeutic ERCP in children are reviewed. ERCP, when used properly, improves the ability of the clinician to diagnose and treat. Therapeutic ERCP reduces the need for surgery, and preoperative ERCP provides surgeons with a "road map" when surgery is required.