Technical Abstract: In the United Kingdom and Australia sheep have been implicated as sources of Cryptosporidium and Giardia that affect humans but no such studies have been conducted in North America. Therefore, a study was undertaken to investigate their prevalence in sheep on a farm in Maryland in which feces were collected from 32 pregnant ewes 1, 2, and 3 days after parturition, and from each of their lambs 7, 14, and 21 days after birth. Samples were examined by immunofluorescence microscopy to determine the presence of Cryptosporidium oocysts and Giardia cysts and subjected to DNA extraction, PCR and gene sequence analysis to determine the species and genotypes. PCR consistently detected higher numbers of positive specimens- the prevalence of Cryptosporidium in ewes and lambs being 25 and 77.4%, respectively. Three species/genotypes of Cryptosporidium were identified as: C. parvum, Cryptosporidium cervine genotype, and a novel Cryptosporidium genotype (ovine genotype). Cryptosporidium parvum and the cervine genotype have been reported worldwide infecting humans. The ovine genotype was reported for the first time. The prevalence of Giardia in ewes and lambs was 12 and 4%, respectively, most infected with Assemblage E which is not zoonotic, one ewe infected with zoonotic assemblage A. Two lambs infected with C. parvum and one ewe infected with G. duodenalis assemblage A represents a low prevalence of these zoonoses. However, high numbers of sheep with the zoonotic cervine genotype indicates that sheep should be considered as a potential source of human pathogens in the environment.