Gastroesophageal submucosal hematoma is a disease in which blood vessels in the gastroesophageal submucosa rupture and form a hematoma. In this report, we describe a case of gastroesophageal submucosal hematoma that developed due to vomiting in a patient with no history of bleeding and resolved with conservative treatment. A 69-year-old man presented with precordial pain and hematemesis after vomiting. A diagnosis of idiopathic gastroesophageal submucosal hematoma was made by computed tomography scan, magnetic resonance imaging, and esophagogastroduodenoscopy. Healing was achieved by conservative treatment with fasting, rehydration, and acid suppression. When a patient presents with sudden chest pain, hematemesis, and dysphagia, the possibility of this disease should be considered.