Aneurysms caused by atherosclerosis are relatively frequent, as a consequence of the high incidence of this degenerative disease of the arteries. Other types of aneurysm, for example, those of infectious etiology, are more uncommon. Bacterias and fungi are able to cause aneurysms in several parts of the arterial tree. Stengel et al (1943), in a review of world literature described 217 cases of mycotic aneurysms. The Stedman's Medical Dictionary refers to a special type of aneurysm observed in horses, caused by intra-vascular migration of a worm, the Strongylus vulgaris. It has been named verminous aneurysm and generally involves the mesenteric arteries. We haven't found in medical literature any similar observations refering to human cases. The purpose of this paper is to describe a case of aneurysm the etiology of which we have imputed to the filaria (Wuchereria bancrofti). This case was observed in Marcilio Dias Naval Hospital, Rio de Janeiro, Brazil.