Cryptosporidiosis represents a major public health problem which transmitted by contamination of food or water by sporulated Cryptosporidial oocyst. Causing self- limited diarrhea in immunocompetent person and chronic and life threatening diarrhea among immunocompromised individuals. It can be diagnosed by concentration and detection of its Oocyst in different environmental samples and water by microscopic and immunological examination such as enzyme immunoassay (ELISA) for parasite antigens and nucleic acid amplification assay as well as use of molecular techniques such as Polymerase Chain Reaction (PCR). Treatment is face challenges, Macrolides, Paramomycin, Nitazoxanide and Mirazid. All these drugs have partial efficacy in reducing disease severity in immunocompetent individuals. Nitazoxanide has partial efficacy in immunocompromised individuals. Resolution of Cryptosporidiosis can be maintained with effective Highly Active Antiretroviral Therapy (HAART).