We describe a 39-year-old patient with an unusual type of bilateral temporal arteritis characterized histologically by inflammation, diffuse eosinophilic infiltration, destruction of elastic tissue, and fibrosis. In addition, the patient had a history of systemic vasculitis, peripheral eosinophilia, eosinophilic lymphadenitis, and membranous glomerulonephritis. The patient has been followed up for 14 years and is well controlled on moderate doses of steroids. We propose that this patient suffers from an immune reaction to an unknown, possibly infectious, antigen.