We report an apparently unique case where hepatitis C virus (HCV) RNA was identified in renal tissue from a patient with membranoproliferative glomerulonephritis and treated chronic hepatitis C, despite the absence of detectable virus in the serum or liver (COBAS Amplicor qualitative assay, lower limit of detection 50 IU/ml). The implications of this finding are discussed, with particular reference to current concepts regarding 'occult' hepatitis C infection.