Gastric marginal zone B cell lymphoma of the MALT type (MALT lymphoma) is usually accompanied by a Helicobacter pylori (H. pylori) infection. Most gastric MALT lymphomas regress after the eradication of H. pylori. Therefore, H. pylori eradication therapy is an effective first-line treatment for gastric MALT lymphoma. A second-line treatment for patients who fail to respond to eradication therapy, including radiotherapy and chemotherapy, produces a good response and survival rate. We encountered 2 cases of H. pylori eradication-resistant gastric MALT lymphoma, which were treated with cyclophosphamide monotherapy. A complete response was obtained in both cases after a treatment duration of 3 months and remission continued for 15 and 18 months, respectively. Treatment-related toxicity was mild. Oral monochemotherapy might be an alternative, effective and safe treatment modality for patients with gastric MALT lymphoma who are resistant to H. pylori eradication therapy. (Korean J Gastrointest Endosc 2010;40:175-180)