BACKGROUND: Hepatolithiasis is a postoperative complication of hepaticojejunostomy (HJ) performed for various pancreatobiliary diseases. Hepatolithiasis can cause repeated cholangitis. Complete stone removal and bile stasis elimination are therefore necessary. Here, we evaluated the effectiveness of peroral direct cholangioscopy (PDCS) using an ultraslim endoscope for treating hepatolithiasis in HJ patients. METHODS: We studied 14 patients with hepatolithiasis who underwent bowel reconstruction with HJ between April 2012 and May 2014. Diagnostic and therapeutic endoscopic retrograde cholangiography using a short double-balloon enteroscope (DBE) was initially performed. Following stone removal, the DBE was exchanged for an ultraslim endoscope through the balloon overtube for PDCS. RESULTS: The success rate of PDCS procedure was 85.7% (12/14). In 5 of 12 (41.7%) patients with successful PDCS, the residual stones were detected and removed completely using a 5-Fr basket catheter and suction after normal saline irrigation. In the remaining 7 (58.3%) patients, no residual stone was detected. The median procedure time was 14 min (range 8-36) with no serious postoperative complications. The median follow-up time after PDCS was 21 months (range 5-26), and only 1 patient (8.3%) had IHBD stone recurrence with an anastomotic stricture. CONCLUSIONS: PDCS using an ultraslim endoscope appears to be useful for detecting and removing residual stones following hepatolithiasis treatment using a DBE. The combined use of a DBE and PDCS may reduce the risk of hepatolithiasis recurrence in HJ patients.