An elderly man with ocular type myasthenia gravis (MG) was found to have monoclonal gammopathy (IgM). Waldenström's macroglobulinemia (WM) was proven later. This is the second case report of MG associated with WM. However, this case is unique due to the presence of anti-acetylcholine receptor (anti-AChR) antibody (IgG). MG is considered to be an autoimmune disease and WM an immunoproliferative disorder. The association of MG and WM is not clear.