Endoscopic ultrasound (EUS)-guided transgastric drainage has been performed as a less invasive procedure for pancreatic fistulas and intra-abdominal abscesses occurring after surgery in recent years. However, there are no reports of EUS-guided transgastric drainage of intra-abdominal abscesses following gastrectomy. This case report describes 2 patients who developed an intra-abdominal abscess following gastrectomy and underwent EUS-guided transgastric drainage. Both patients underwent laparoscopy-assisted distal gastrectomy with Billroth-I reconstruction for gastric cancer. The intra-abdominal abscesses were caused by postoperative pancreatic fistula that developed following gastrectomy. One patient underwent naso-cystic drainage and the other underwent only a needle puncture of the abscess cavity. EUS-guided drainage was performed safely and effectively, although 1 patient developed gastroduodenal anastomotic leakage related to this procedure. In summary, EUS-guided transgastric drainage is safe and technically feasible even in post-gastrectomy patients. However, it is necessary to be careful if this procedure is performed in the early period following gastrectomy.