Endoscopic submucosal dissection (ESD) is now recognized as the preferred treatment modality for gastrointestinal epithelial lesions. A 21-month-old female was admitted with a giant hyperplastic polyp causing a gastric outlet obstruction. Successful ESD was performed with caution. The post-procedural course was uneventful without a bleeding episode. Although further study of the feasibility of ESD in early children is necessary, ESD could be applied to avoid laparotomy even in young children.