Pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma is a rare extranodal lymphoma with a 5-year survival rate of 80-95 %. There is no standard treatment strategy for pulmonary MALT lymphoma. In the present study, we performed a retrospective evaluation of systemic rituximab monotherapy (375 mg m(-2) day(-1), 4-8 cycles) as first-line treatment in patients with pulmonary MALT lymphoma. Of the eight patients enrolled, five achieved complete response, one achieved partial response, and two showed stable disease. Median progression-free survival was 66.0 months (range 9.7-87.2 months). Treatment was well tolerated and all patients were alive during the median follow-up period of 64.0 months. Rituximab monotherapy was efficacious in patients with pulmonary MALT lymphoma, demonstrating long-term disease stabilization and symptom reduction. Larger prospective studies are warranted to further assess the efficacy of rituximab monotherapy. In conclusion, rituximab monotherapy may be considered for first-line therapy in patients with pulmonary MALT lymphoma.