Cryptorchidism is the most frequent congenital disturbance in males requiring both medical and surgical interventions. The involved testicle shows severe pathological changes. In an effort to test new medical treatments, we established a rat model for induced cryptorchidism using two estradiol treatment regimens and evaluated the effects of GnRH and an analogue D-Phe-GnRH on rate of testicular descent and on improvement of abnormal testicular histology. We found that the duration of estradiol treatment and not the total dose was related to delayed recovery from testicular descent. No significant effect of GnRH on testicular descent was observed. D-Phe-GnRH significantly improved the rate of testicular descent in rats treated 40 days with estradiol, but not in those treated 30 days with estradiol. The histologic examination of estradiol-induced undescended testes revealed severe morphological changes with a low number of germ cells, infiltration with lymphocytes, fibrosis and smaller diameter of seminiferous tubules. These changes were not improved with GnRH. D-Phe-GnRH was able to correct some of the histologic changes of estradiol-induced cryptorchidism. We established an animal model for testing of medical treatments for cryptorchidism. Our study may be indicative of a new treatment strategy using D-Phe-GnRH in the non-surgical treatment of cryptorchidism in human.