The reliability of oral biopsy (OB) and fine needle aspiration biopsy from subcutaneous fat (FNAB) in the diagnosis of secondary amyloidosis was compared using the specimens taken from 124 patients, 107 adults and 17 children, suffering from long lasting rheumatoid diseases. 41 of the patients (33.0%) were shown to be positive for amyloidosis with one or both methods. OB was positive in 28, FNAB in 33, and both methods in 20 patients. In addition, rectal biopsy (RB) was positive in 14 out of 43 cases, where it had been taken. In 3 patients, this method was positive for amyloidosis, although OB and FNAB were negative. Thus, the total number of patients positive for amyloidosis in this study was 44 (35.5%). The mean duration time of the disease was significantly longer in the adult and child patient groups with amyloidosis than in those without amyloidosis. The diagnostic sensitivity of OB was 64%, and that of FNAB 75%. The results speak for the use of FNAB as the first choice method in the diagnosis of secondary amyloidosis.