Monoclonal gammopathy of unknown significance (MGUS) is the most frequent plasma cell disorder that commonly affects elderly patients. Although it is an asymptomatic condition, as well as smoldering myeloma (SMM), the risk of progression to multiple myeloma requiring therapy or other B-cell disorders varies greatly for individual patients, remaining low for MGUS (1% per year), while higher and not uniform for SMM patients (10% per year). This scenario implies some special considerations regarding assessment and follow-up, especially in the elderly.