Ticks and blood samples were collected every month from March 2009 through April 2010 from different sites in Sinai to detect babesial parasites using PCR assay based on nuclear small subunit rRNA gene. Ticks were found to contain babesial DNA. Sequence determination and analysis of amplified portions of nss-rDNA revealed their identity with B. bovis and a high degree of homology with B. bigemina and B. divergens. The results represent the first genetic evidence of different species of Babesia and identified the role of Ixodes ricinus as a vector of zoonotic B. microti infection. Rodent isolate (HK) and American isolate (GI) were studied in transmission experiments. The present study used in vitro culture of zoonotic Babesia sp. EU1 from blood samples of rodent in Sinai. This study provides an evidence of transovarian and transstadial transmissions of the parasite within I. ricinus, which emphasizes that this tick could be a vector and reservoir of EU1