Familial Mediterranean fever (FMF) is a genetic disorder virtually restricted to people originating from the Middle East. It is characterized by short, self-limiting, febrile attacks of peritonitis, synovitis, pleuritis or an erysipelas-like erythema. Without treatment systemic amyloidosis often develops and causes death in renal failure, usually at an early age. Two siblings with FMF and renal amyloidosis are presented. One had nephrotic syndrome, the other severe proteinuria. Continuous colchicine treatment reverse the nephrotic syndrome and in both patients the proteinuria was reduced. It is concluded, that even though colchicine can improve severe renal amyloidosis, early diagnosis of FMF is crucial because continuous colchicine treatment prevents both the febrile attacks and the amyloidosis.