Mucous membrane plasmacytosis (MMP) is a rare idiopathic condition characterized by infiltration of the mucosa by non neoplastic plasma cells. In this report we describe a case of mucous membrane plasmacytosis of the nose in a 72-year-old woman patient affected by B-cell chronic lymphocytic leukemia (B-CLL). Two different biopsies of the lesion showed diffuse plasma cell, lymphocyte and granulocyte infiltration compatible with granulation tissue. A complete exeresis of the neoplasm was performed endoscopically without complications, allowing the diagnosis of MMP; a monthly follow up was performed with no signs of local relapse 15 months after surgery. Topical steroid therapy with budesonide nasal spray was administered. There is no standardized treatment for MMP: we have reported good result of surgical approach in a unique case of nasal MMP in a patient with B-CLL; the relation between these two diseases deserves more studies.