Cryptosporidium species are apicomplexan parasites that infect the microvillus border of the gastrointestinal epithelium of a wide range of vertebrate hosts, including humans.Infected individuals show a wide spectrum of clinical presentations, but the pathogenicity of Cryptosporidium varies with the species of parasites involved and also the type, age, and immune status of the host. Cryptosporidium infections are associated with only acute, self-limiting illness while in animals or individuals who are immune-suppressed; the infection is frequently chronic and can eventually be lethal. Occasionally food sources may serve as vehicles for infection transmission and many outbreaks had occurred in water parks, community swimming pools, and daycare centers. Zoonotic and anthroponotic transmission of Cryptosporidium spp. occur through exposure to infected animals or exposure to water contaminated by feces of infected animals. This book highlighted on the zoonotic significance of cryptosporidiosis and also classification, life cycle, epidemiology, and recent advances and trends in diagnosis, preventive measures and control of this parasite have been also taken in consideration