This case involved a 75-year-old man who underwent mediastinoscopic subtotal esophagectomy, three-field lymph node dissection, retrosternal gastric tube reconstruction, and enterostomy for lower thoracic esophageal cancer. Enteral feeding was started through the enterostomy from post-operative day 1, and the dosage was gradually increased because anastomotic leakage occurred. On post-operative day 20, severe abdominal pain developed, and a contrast-enhanced computed tomography (CT) revealed portal venous gas and pneumatosis intestinalis. Since intestinal necrosis was suspected, the patient received emergent operation. There was no apparent evidence of ischemia, and the surgery was finished as exploratory laparotomy. Although enteral feeding was resumed on the fifth post-operative day, there was no recurrence, and the patient was discharged from the hospital. Portal venous gas and pneumatosis intestinalis associated with enteral feeding are rare complications and are not widely known in Japan. As we have encountered a case of portal venous gas and pneumatosis intestinalis following surgery for esophageal cancer, herein the case is reported with some bibliographical discussion.