Cryptosporidiosis is an infection caused by Cryptosporidium, a protozoan parasite of clinically importance. It is transmitted by contaminated water and in individuals with proper immune systems it usually causes diarrhea, but in case of immunocompromised people, like those suffering of AIDS, the disease is usually severe and it can be fatal. It is known to be zoonotic in nature. In other words, Cryptosporidiosis can be spread naturally directly from cats to their keepers. Oocyst is a critical stage and mainly responsible for causing infection with typical gastrointestinal manifestations in humans. Medically important ones are C. parvum and C. hominis, causing infections. The classic symptoms include watery diarrhea, nausea, vomiting, abdominal cramps and Fever etc. The infection is self-limiting so oral o as well as intravenous rehydration and replacement of electrolytes are usually suggested. Moreover, the best of avoiding is to promote the practices of hand washing and hygienic standards in the mass.