In the past years the global population of the particular species of the amphibians has reduced. In this article the authors review all the ecological factors having influence on the development of amphibians, especially concentrating on chytrid fungus. Postulated causes of the deformities and population declines include ultraviolet radiation, climatic changes, agrochemicals, especially pesticides, parasites, eutrophication of the water bodies and road factors. In the past years attenuation of the populations of amphibians by specification of the ecological factors caused damage to the chytrid fungus Batrachochytrium dendrobatidis. Authors examine this occurrence in particular continents and described its biology. Batrachochytrium dendrobatidis were noticed for the first time in Poland in 2009.