Splenic marginal zone lymphoma (SMZL) is a rare type of non-Hodgkin's lymphoma (NHL). We report here on a patient who displayed the synchronous occurrence of SMZL and early gastric cancer (EGC). The patient was a 74 year-old male with liver cirrhosis. An EGC in the gastric antrum was diagnosed and the preoperative abdomen computed tomography scan revealed splenomegaly and intra-abdominal lymphadenopathy. We performed subtotal gastrectomy and the postoperative pathologic examination revealed adenocarcinoma limited to the gastric mucosa and SMZL in the lymph nodes. The patient recovered from the surgery without complications and is now awaiting chemotherapy. SMZL has an indolent clinical course with good long-term survival and so there is the possibility of the occurrence of a second primary malignancy. Rare cases of a second primary malignancy being diagnosed along with SMZL have been described in the literature. Patients with SMZL should be carefully followed after treatment to detect the possible occurance of a second primary malignancy.