To our knowledge there are only a few reports showing a role of eradication therapy for H. pylori in the treatment of low-grade MALT-lymphoma, of stage EI2. We report a rare case of MALT-lymphoma, invading all of the gastric wall, which regressed after eradication of H. pylori. The regression was well documented by endoscopic ultrasonography (EUS). A 70-year-old man was referred to us for upper endoscopy that showed a single ulcer of 3cm in diameter at the gastric angulus. Histology, immunohistochemistry and PCR analyses diagnosed a low-grade MALT-lymphoma in the presence of H. pylori infection. EUS showed a tumor invasion of all the gastric wall. The serosa layer, also, appeared irregular and interrupted in some points. The lymph nodes around the duodenum and the stomach were not involved. An anti-H. pylori therapy was started. After 1 year from the diagnosis, EUS showed the reappearance of the normal layers of the stomach. The patient is actually disease free. This result suggests that in EI2-stage gastric lymphoma of MALT type, in the absence of both high-grade malignancy foci and t(11;18)(q21;q21) chromosomal translocation, an eradication treatment may be considered as a first therapeutic option.