Mucosa-associated lymphoid tissue lymphoma (MALT lymphoma) is an indolent B-cell lymphoma characterised by a fascinating interplay between chronic antigenic stimulation, an immune response insufficient for elimination of the antigen and a mucosal 'battleground'. The archetype of this association is infection of the gastric mucosa with (): a single course of antibiotic -eradication treatment may result in long-term remission in up to 80% of patients and is the gold standard for first-line therapy of -associated gastric MALT lymphoma. In extragastric or disseminated disease, treatment options range from wait and see in asymptomatic individuals to radiotherapy in localised stages, anti-CD20-antibodies in patients with low symptomatic burden and chemotherapy-based treatment or radio-immunotherapy in symptomatic disease. In addition, more refined immunomodulatory strategies beyond simple eradication of bacteria such as long-term use of the macrolide clarithromycin or the immunomodulatory drug lenalidomide are active. In view of the indolent clinical course, the least toxic individual treatment should be chosen in a disease usually not influencing overall survival in affected patients.