A 50-year-old man experienced sudden chest pain radiating into his left shoulder about 16 months after undergoing an open splenectomy for malignant splenic lymphoma. As the patient did not respond to conservative therapy, he was transferred to our hospital. Computed tomography of the chest showed that the upper stomach had herniated into the thoracic cavity. Emergency surgery revealed that the hernial sac was partially torn and open to the thoracic cavity. We sutured the hernial orifice closed and performed Dor fundoplication. Although sporadic reports on this type of hernia following laparoscopic surgery have been reported, delayed diaphragmatic hernia following open splenectomy is rare.