For different reasons amyloid deposits may not be observed with Congored (CR) staining method. Congo red fluorescence (CRF) is suggested to be more sensitive. In this study, renal biopsy frozen and paraffin sections stained with CR were studied under fluorescence microscope for CRF. 82 frozen, 34 paraffin and 20 paraffin plus frozen sections were studied with CRF. In 15 of the patients (13 AA, 2 AL) amyloid deposits were observed. Between frozen and paraffin sections, CR and CRF false positive and negative results have not been observed. But two of the cases which were negative for amyloid deposits on the previous biopsy, were diagnosed as amyloidosis with CRF. Because of this two cases which were amyloid negative with CR, we think that CRF is more sensitive than CR. CRF can be used both with frozen and paraffin sections. As a routine, CR stained section could be added to immunofluorescence study panel. Cases which are observed under light microscope as amyloid negative, should be studied with CRF before final diagnosis.