We describe a 14-year-old boy with a 5-year history of familial Mediterranean fever (FMF), treated with colchicine, who developed polyarteritis nodosa (PAN). He was admitted to our hospital with fever, general weakness, arthritis, and purpura. Five weeks after admission, hypertension was noted. Skin biopsy showed perivascular leukocyte infiltration in the epidermis. An aortography revealed multiple aneurysms of the renal, common hepatic, and intercostal arteries. He was treated with intravenous methylprednisolone, oral cyclophosphamide, and azathioprine. The known rare association of FMF and PAN is discussed.