A subcutaneous mass foud in a nine-year-old male Iguana (Iguana iguana) was pathologically and microbiologically examined. Grossly, this mass, measuring $2 cm{ imes}1.5 cm{ imes}1 cm$ in size, contained white to yellow caseous-crumbly material which was surrounded by the thin connective tissue. Histopathologically, a mass consisted of central caseous necrotic debri in which heterophils and macrophages were scattered, and peripheral fibrous connective tissue in which scattered heterophils, macrophages and lymphoid cell aggregates were present. This mass composed of central necrotic core and peripheal connective tissue did not have any detectable microorganisms including acid-fast bacteria and fungi. Histopathologically, severe atrophy of seminiferous tubules in both testicles was observed. In addition, peripheri of ductus deferens was thickened by fibrous connective tissue. This is the first report of subcutaneous caseous necrotic mass of an Iguana in Korea. In addition, the bilateral severe atrophy of seminiferous tubules may be due to fibrosis of ductus deferens.