The deposition of copper on Descemet's membrane and the anterior and posterior lens capsule with extreme hypercupremia and IgG hypergammaglobulinemia has been previously described with multiple myeloma and pulmonary carcinoma. A 66-year-old man presenting with blurred vision was found to have bilateral golden-brown metallic dust-like deposits on the central region of Descemet's membrane and the anterior and posterior lens capsule. Laboratory investigations revealed an elevated serum copper level 10 times the normal level associated with a monoclonal gammopathy and a normal ceruloplasmin level. Copper binding to the serum proteins was investigated by three biochemical methods. The results demonstrated that the major copper binding fraction in the serum was IgG. N-terminal amino acid analysis of the IgG did not find the sequence of Asp-Ala-His, which has been shown to be a copper binding site in albumin. This is the first report of benign monoclonal gammopathy being associated with the ocular deposition of copper.