Endoscopic mucosal resection (EMR) has been accepted as a completely curative treatment of gastrointestinal mucosal cancers. With advances in diagnostic techniques, the tendency to detect simultaneous multiple primary cancers is increasing. Patients with another cancer coexisting with esophageal cancer have had a poor prognosis, but if both cancers are detected in the early stage, complete treatment consisting only of endoscopic surgery, with a good prognosis, is expected. We describe two cases of simultaneous multiple early cancers of the stomach and esophagus, treated by EMR.