We present a case of Churg-Strauss syndrome complicated by chronic periaortitis. A 68-year-old man presented with wheezing, dyspnea, purpurae, and numbness of the extremities. Antineutrophil cytoplasmic antibodies were absent; however, eosinophilia, a pulmonary infiltrative shadow on chest X-ray, eosinophilic vasculitis on histologic examination of skin and kidney, and mononeuritis multiplex were detected. Churg-Strauss syndrome was diagnosed. Contrast-enhanced abdominal computed tomography revealed a periaortic soft tissue mass extending from the subphrenic abdominal aorta to the proximal area of the bilateral iliac arteries. This indicated chronic periaortitis, probably caused by vasculitic activities. Both disorders improved with steroid therapy.