SUMMARY   In Fayoum Governorate, a total of 196 milk samples were collected aseptically from apparently healthy functioning glands of 163 dairy ewes to study subclinical mastitis (SCM) in dairy ewes. According to the definition of SCM the only sample that showed California Mastitis Test (CMT) and bacteriology positive results was considered to have subclinical mastitis, the prevalence of SCM was 29.45% in regard to ewes and 31.63% in regard to glands. Subclinical mastitis was higher in multiparous ewes (32.03%) than primiparous ones (20.0%), but this increase is not statistically significant. CMT was useful as a screening test in ovine species to identify infected animals, keeping in mind that the test showed higher prevalence rate of subclinical mastitis than bacteriological culture (55.61% compared with 39.80%). Staphylococci were the most common bacteria detected (73.08% isolates), where coagulase-negative staphylococci (CNS) were detected in 50% of CMT positive samples isolates and in 48.72% of the total bacterial isolates and Staphylococcus aureus (S. aureus) was isolated in a percentage of 30.65% only from CMT positive samples followed by Streptococcus agalactiae (S. agalactiae) in 9.68% of CMT positive samples isolate and lastly Escherichia coli (E. coli) in 4.84% of CMT positive samples isolate and in 14.10% of the total bacterial isolates. Yeast was also detected in 4.84% of the CMT positive samples isolate and in 5.13% of the total isolates. Enzymatic activities of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) proved to be good indicator for intramammary infection in ewes, where, enzymatic activities of LDH and ALP were significantly higher (p < 0.05) in milk from subclinically mastitic ewes compared to milk from healthy ones. On the other hand, there were no significant alterations recorded in the levels of serum LDH and ALP of subclinically mastitic ewes compared to healthy ones.