We contend that patients presenting with Congo-red-negative fibrillary deposits on renal biopsy should be evaluated carefully for monoclonal-gammopathy and cryoglobulins, but there is insufficient published data, as yet, to justify subclassification of FG and ITG as distinct clinical entities. Indeed, we argue that it remains to be determined if FG-ITG represents a unique condition or a forme fruste of cryoglobulin- or gammopathy-associated renal disease. Although the optimal treatment for FG-ITG has not been determined, renal transplantation appears an attractive option in patients with end-stage renal failure.