Abstract: The aim of the present study was to determine Cryptosporidium species and genotypes in cattle by molecular methods. Fecal samples were collected from 104 adult cattle in a slaughterhouse in Tabriz, Northwestern Iran during the period from June to July 2007. Initial identification of cryptosporidiosis was carried out by formalin-ether concentration and Kinyoun acid fast staining method. Genomic DNA was extracted from microscopically positive samples and nested PCR was performed to amplify the partial small-subunit rRNA gene of Cryptosporidium that were subsequently digested by restriction enzymes to determine the Cryptosporidium species and genotypes present. In this study Cryptosporidium parasites were found in 10.5% (11 cases) adult cattle. Among 11 analyzed isolates, two different species of Cryptosporidium were identified; 64% (seven cases) of isolates belonged to C. andersoni and 36% (four cases) to the potentially zoonotic species of C. parvum bovine genotype. The results of present study showed that two species of Cryptosporidium, C. andersoni and C. parvum bovine genotype are responsible for cattle cryptosporidiosis in this region and the existence of C. parvum bovine genotype suggest that there is a potential risk of zoonotic transmission of C. parvum bovine genotype infection between cattle and human, likely by means of contaminated water or food, or through direct contact in the farmers and veterinary staff.