An imported 2.5-yr-old female green iguana (Iguana iguana rhinolopa) kept in Greece was presented with a history of anorexia and allotriophagy of 1 mo duration. Upon clinical examination, it was cachectic and had severe abdominal distension and fibrous osteodystrophy. Despite treatment, it died a month later. On necropsy, massive accumulations of threadlike nematode parasites were observed in the large intestine, identified as Ozolaimus megatyphlon, a member of the Oxyuridae family of Pharyngodonidae, a usually nonpathogenic intestinal parasite of iguanas. To the authors' knowledge, its presence has not been reported previously in Europe, although one pathogenic infection has been reported previously in Japan. The animal was presumably infected before importation. Although death was attributed to the heavy parasitic overload, the poor diet and terrarium hygiene, and absence of an anthelminthic regime further contributed to the deterioration of the animal's condition. Recognition of this condition, which may be recently introduced or underdiagnosed, may help improve medical and trade standards concerning this species in practice.