A fistulous tract between the stomach and the spleen is a rare manifestation. Spontaneous gastrosplenic fistula formation resulting from primary gastric lymphoma is extremely rare and should be managed as an emergency. To date, four gastrosplenic fistulas originating from gastric lymphoma have been reported, of which three were spontaneous and one occurred following chemotherapy. We report a case of spontaneous gastrosplenic fistula in a 35 years-old-man with gastric malignant B-cell non-Hodgkin's lymphoma who was diagnosed by computed tomography and endoscopically, followed by successful treatment with total gastrectomy and splenectomy.