Protozoa of the genus Cryptosporidium spp. are often an underestimated problem in livestock farms and poultry flocks. On account of difficult and time-consuming diagnostic methods cryptosporidiosis is rarely confirmed by laboratory tests. Occurring cases of persisting diarrhea are treated without a proper diagnosis. In addition, the lack of effective veterinary preparations on the market reduces treatment options. According to available literature, the estimated prevalence of Cryptosporidium spp. in cattle herds ranges from 17 to 100%. In the case of poultry flocks there is no accurate data. The paper presents the current state of knowledge about the biology, presence, methods of diagnosis, and treatments of Cryptosporidiosis.