We conducted this study to to evaluate the usefulness and safety of endoscopic retrograde cholangiopancreatography (ERCP) in children. Retrospective study. During 9 years, 114 ERCPs were attempted in 58 children. The children were 31 boys and 27 girls and their mean age was 9.5 years old (2months - 18years). Twenty attempts were done under general anesthesia and the rest were done under deep sedation. The cannulations were successful in all but two attempts with neonatal cholestasis. The indication for ERCP was biliary disease in 33 and pancreatic disease in 25 children. We conducted endoscopic sphincterotomy (EST) in 51, ENBD or ENPD in 33, stent insertion in 9, balloon extractions in 5, and balloon dilatations 5 cases. Among 58 children with successful cannulation, we could confirm the clinical diagnosis in 26, add the additional information in 10, and revised the diagnosis in 8; however no further diagnosis were added in 14 even after ERCP. The diagnosis after ERCPs are choledochal cyst (9, with AUPBD 6), chronic pancreatitis (8), CBD stone (7, with AUPBD 2), acute pancreatitis with CBD stone or GB sludge (6), bile duct stricture (3), pancreatic transsection with trauma (2), IHBDP (3), pancreatic fistula (1), sclerosing cholangitis with histiocytosis (1), liver laceration with trauma (1), bile peritonitis with leak after LRLT (1), choledochocele (1), recurrent pancreatitis with AUPBD (1), and normal ERCP finding (14). The therapeutic procedures were done in 61 attempts. Operation guidances were done in 8 cases. As complications of ERCP, acute pancreatitis developed in 3 children, septic complication in 3, moderate delayed hemorrhages requiring transfusion in 2, and retroduodenal perforation in 1 child. Transient hyperamylasemia and lipasemia were observed in 51 procedures but resolved within 2 to 5 days post-ERCP. No fatality was observed and all complications could be managed with supportive cares. Most complications developed especially after EST. We concluded that ERCP may provide more definite diagnosis, preoperative guidance and endoscopic therapy in children with pancreatic or biliary disorders. But special care should be paid especially with EST.