Primary gastric lymphoma derives from a secondary MALT system developing after a reaction of the immune system, e.g. following chronic gastritis induced by Helicobacter pylori. Morphologically, follicular hyperplasia is found in the gastric mucosa. The pathoetiologic model confirms the transformation of a malignant lymphoma from low grade to high grade by demonstrating increasing autonomous proliferation and, finally, uncontrolled dissemination. Modern diagnostic tools are essential for staging and planning an adequate therapeutic strategy. At present, the therapeutic strategies regarding primary lymphoma are under discussion. Nevertheless, the consensus of international medical and surgical associations still recommends surgical therapy with curative intention for low-grade malignant lymphomas staged I 2-II 2. In cases of high-grade malignant lymphoma, conservative therapy is supposed to be similarly successful. The recent success of noninvasive therapeutic concepts seems to justify the application of triple eradication medication in case of Hp infection as well as radio- and chemotherapy in low- and high-grade malignant lymphomas. However, in cases of nonremission or therapy-associated complications such as uncontrollable bleeding or tumor perforation, surgery is the only therapeutic option. Regarding the oncological aspects of lymphoma growth, surgery should then be performed in order to achieve R0 resection.