Waldenström's macroglobulinemia is a distinct clinicopathologic entity defined as a B-cell neoplasm characterized by lymphoplasmacytic infiltrate in the bone marrow, with an associated immunoglobulin (Ig) M paraprotein. Clinical manifestations are due to deposition of IgM in the liver, spleen, and/or lymph nodes, so it presents with anemia, hyperviscosity, lymphadenopathy, hepatomegaly, splenomegaly and neurologic symptoms. The main diagnostic criteria are a typical peak on serum protein electrophoresis and malignant cells in bone marrow biopsy samples. There is no standard therapy for the treatment of symptomatic Waldenstrom's macroglobulinemia and no agents have been specifically approved for this disease, but initial treatment usually starts with the monoclonal anti-CD20 antibody rituximab, either alone or in combination with other agents, rather than chemotherapy alone. This article confirms that, despite the existence of more modern imaging methods, ultrasonography still has a significant diagnostic role.