Objectives: Although no part of the human anatomy is invulnerable to hydatid disease, it has been reported to occur mostly in vital organs such as liver, lungs and brain. Hydatid disease of the urinary tract is uncommon accounting for only 2% of all such cases. Testes are extremely rare sites for echinococcosis. To our knowledge there are only 3 cases of testicular hydatid cyst described. In this animal model, we studied echinococcosis in rabbit testis. Methods: We directly infected the unilateral testis of 4 male rabbits with infective protoscolices via intratesticular injection and housed them under pathogen-free conditions for 10 weeks. All rabbits survived during the follow-up period and then, at the 10th week, all testes were removed for histopathologic investigation. Results: Despite of the direct infection of the rabbit testes with Echinococcus granulosus, there was no demonstrable hydatid cyst after a 10-week period except from some fibrosis in the injection tract of the testicular tissue in 1 case. Conclusion: The testes are extremely rare anatomic locations for echinococcosis infection. The mechanism of this resistance should be another reason apart from blood-testicular barrier. We think that low temperature in the scrotum or different properties of the testicular tissue may be the reasons of this defense mechanism. If this hypothesis clarifies with the further studies, new treatment options may be defined in the medical literature for the hydatid cyst. Copyright (C) 2004 S. Karger AG, Basel.