Symptomatic Meckel's diverticulum is an uncommon diagnosis in adults, and bleeding Meckel's diverticulum after childhood is even more infrequent. We present herein the case of a 22-year-old man with gastrointestinal hemorrhage secondary to Meckel's diverticulum containing ectopic gastric mucosa. As the source of bleeding could not be identified by upper and lower gastrointestinal endoscopy and visceral selective angiography, the new methods of capsule endoscopy and double-balloon endoscopy were used. Capsule endoscopy showed oozing hemorrhage in the ileum, and double-balloon endoscopy demonstrated a large diverticulum in the distal part of the ileum. Tc-99m pertechnetate Meckel's scan revealed an abnormal focus of uptake in the right lower abdomen. The diverticulum was resected laparoscopically. The postoperative course was uneventful, and the patient remains in complete remission as of this writing. Detecting Meckel's diverticulum endoscopically is difficult prior to surgery, but a combination of capsule endoscopy and double-balloon endoscopy facilitates examination of the entire small intestine, making precise diagnosis of Meckel's diverticulum possible.