Monoclonal gammopathy of unknown significance (MGUS) is a chronic haematological alteration that carries a 1% risk per year of malignant evolution. The origin of this disturbance remains unknown. Previous reports have suggested that a subgroup of patients presenting MGUS might cure after Helicobacter pylori eradication. This study evaluates the effect of H. pylori eradication in a cohort of 30 patients with MGUS. A 7-day clarithromycin-based triple treatment was prescribed to patients with MGUS infected with H. pylori. Quantification of the monoclonal component was performed at inclusion and at least 12 months after treatment. The monoclonal component persisted unchanged in all patients who cured the H. pylori infection.