Enteral feeding with nasogastric tube is widely used because of its convenience in patients without volitional intake. If the position of the tip of the nasogastric tube is above the gastroesophageal junction, there is possibility of retention and solidification of the administered enteral feeding formula in the esophagus. Even if its position is confirmed by auscultation, all or some of the side holes of nasogastric tube may be located above the gastroesophageal junction. Therefore, the tip of the nasogastric tube should be checked carefully, with considering to use chest radiograph especially in patients who have higher risk of aspiration, gastroesophageal reflux. This paper describes two unusual cases of esophageal obstruction caused by solidification of the residue of enteral feeding formula that is administered through a malpositioned nasogastric tube. The first case is 87-year-old female who had no past medical history and was diagnosed pneumonia, and the second case is 68-year-old male who had diabetes mellitus and was diagnosed ascending aortic pseudoaneurysm, acute cerebral infarction.