The simultaneous association of gastric carcinoma with gastric lymphoma is a rare event. Recent studies have suggested that not only gastric cancer but also primary gastric lymphomas, especially those of mucosa-associated lymphoid tissue (MALT) type, are associated with Helicobacter pylori infection. We report on a 51-year-old woman who was referred to our hospital for the evaluation of abnormal shadows revealed by an upper gastrointestinal radiography series. Endoscopy of the upper gastrointestinal tract revealed early cancer in the middle body of the stomach. Biopsy of the lesion subsequently proved it to be a signet-ring cell carcinoma. Total gastrectomy was performed, under a diagnosis of early gastric carcinoma. The resected specimen revealed two grossly separate lesions. Histological examination confirmed that the gastric body lesion was compatible with early moderately differentiated tubular adenocarcinoma of type 0-IIc, while the lesion of the fundus corresponded to MALT lymphoma. H. pylori was detected, and chronic gastritis was also present in the resected gastric specimen. H. pylori infection may have played a major role in the development of both the MALT lymphoma and the adenocarcinoma of the stomach in this patient.