Percutaneous drainage, percutaneous transgastric drainage, and endoscopic ultrasound (EUS)-guided transgastric drainage are primarily utilized for drainage of fluid collections dorsal to the stomach. Percutaneous transgastric drainage is performed with computed tomography (CT) guidance, but it requires inflation of a balloon in the stomach, and gastric peristalsis makes it difficult to ensure a reliable puncture route via the stomach. Using endoscopy-assisted CT-guidance, we were able to safely and effectively perform percutaneous transgastric drainage. A 69-year-old man underwent a pancreaticoduodenectomy for cancer of the inferior section of the common bile duct. Postoperative day 5, the amylase value of the drainage fluid was 1,232 IU/L, we diagnosed a pancreatic fistula developed as a result of pancreaticojejunal anastomotic failure and we performed drainage at the drain which was placed in the foramen of Winslow intraoperatively, however fluid collection dorsal to the stomach was detected on a follow-up abdominal CT scan, and the fluid was a high value of amylase, we judged the drain was not working well and the pancreatic fistula occured. Endoscopy-assisted, CT-guided percutaneous transgastric drainage was therefore performed, and the pancreatic fistula was successfully closed the fistula.