In OLT patients, stone formation appears to occur at an accelerated rate compared to the general population because of associated recurrent biliary tract infection, epithelial shedding, cyclosporine use and biliary strictures. We report the endoscopic findings and treatment results in OLT patients with a duct-to-duct anastomosis (DDA). Patients and Methods: From 5/88- 8/99, 412 OLTs were performed and 121 OLT patients with DDA underwent 325 ERCPs for evaluation of cholestasis. All duct stone patients underwent attempted endoscopic stone extraction following endoscopic sphincterotomy (ES), biliary stricture dilation or stone lithotripsy if needed. Results: Forty-six patients were found to have stones (n=37)or sludge (n=9). Stones were identified in 18 patients on T-tube cholangiogram prior to ERCP. Twenty-eight patients presented with cholangitis. Bile duct stones/sludge were detected at a mean of 19.2 months (range 1.8-53.5 months) after transplant. Twenty-nine patients also had biliary strictures and 28 had stone(s) upstream to the stricture. Eleven patients had castlike stones. Stones were located in both the donor and recipient ducts in 14 patients, in the donor duct alone in 18, and in the recipient duct alone in 14. Stones were present in intrahepatic ducts in 7 patients. ES was performed in all cases for stone and sludge removal. Stone removal was successful in all 46 patients and required one ERCP session in 27 patients (58.7%), two sessions in 11 patients (23.9%), and three or more sessions in 8 patients (17.4%). All patients with stones and stricture required at least 2 sessions of endoscopic treatment which included stent placement for stricture management. Recurrent stones were found in 8 patients (17.4%) during follow-up ERCP at a mean of 5.6 months (range 1.9-18.7 months). Conclusion: Endoscopic stone removal in OLT patients with duct-to-duct anastomosis can be performed in the same manner as the general population with choledocholithiasis. However, multiple sessions may be required, especially in patients with an associated stricture. Medical therapy to prevent stone formation/recurrence is needed.