Familial Mediterranean fever (FMF) is an autosomal recessive disease which predominantly affects certain ethnic groups mainly Sephardic Jews, Turks, Arabs and Armenians. FMF has been rarely reported in Japan. Characteristic symptoms include self-limited recurrent attacks of fever with serositis such as peritonitis, pleuritis, and arthritis. The most serious complications of FMF are secondary AA amyloidosis and subsequent chronic renal failure. FMF is caused by mutations in MEFV gene which encodes a protein called pyrin. Pyrin regulates processing of IL-1beta, NF-kappaB activation and apoptosis. Dysregulated function of pyrin results in excessive production of proinflammatory cytokine thereby evoking inflammatory attacks. The mainstay of treatment is colchicine which is effective for both relieving symptoms and preventing secondary amyloidosis.