Immunotactoid glomerulopathy is one of several renal disorders characterized by the extracellular deposition of nonamyloid fibrillary deposits. There is considerable debate as to whether immunotactoid glomerulopathy should be distinguished from fibrillary glomerulonephritis, a closely related entity. Currently, the distinction is based on fibril size and arrangement. We report the case of a 59-year-old woman in whom a diagnosis of immunotactoid glomerulopathy was made after a 2-year history of proteinuria. Electron microscopy of her renal biopsy showed randomly arranged microtubular subepithelial and mesangial deposits, which measured 34 nm in average diameter. She was later discovered to have circulating immunoglobulin G heavy chains without associated light chains (gamma-heavy-chain disease) and, subsequently, non-Hodgkin lymphoma, follicular lymphoma, grade I (World Health Organization classification). Approximately 100 cases of gamma-heavy-chain disease have been reported in the literature since it was originally described by Franklin in 1964. However, while there are 10 reports in the literature of heavy-chain disease with fibrillary deposits in the kidney, none fit the criteria for immunotactoid glomerulopathy.