The aim of this paper was to investigate the effects of germ cell depletion on the sexual differentiation of gonads in five anuran species. We used busulfan to eliminate the germ cells. Our results indicate that germ cells are not required for gonadal ridge formation or the development of the undifferentiated gonads. We observed a gradual degeneration of gonads in studied species and the transdifferentiation of the whole gonads into large fat bodies in Xenopus laevis. In the latter the sexual differentiation of gonads or seminiferous tubules were not impaired in the absence of germ cells. Thus, the X. laevis may serve as a model to study the human Del Castillo syndrome. Our study shows that in anuran amphibians the germ cells are not necessary for the formation of the testis, but they are crucial for development of the ovaries and are required for the maintenance of the gonadal structure.