Two cases of polyarteritis nodosa (PAN) in patients with familial Mediterranean fever (FMF) are reported. These and another 11 cases found in the literature suggest that PAN occurs more commonly in patients with FMF than would be expected in the general population. Perirenal hematoma, which is surprisingly high in patients with FMF, is a life threatening complication of PAN. The diagnosis of PAN in patients with FMF may be delayed due to the similarity of the clinical manifestations of both diseases.