Nine, 5 month old baladi sheep were divided into 3 groups, group I was inoculated with Rift Valley Fever (RVF) virus ZH501strain , group Π was inoculated with RVF virus Smithburn strain, and group ΙΙΙ was non inoculated kept as control. The rectal temperature was recorded and a trial for virus isolation and identification besides following up the antibody response using indirect solid phase ELISA (SPE) were adopted. Group I showed fever continued for 5 to 6 day post inoculation (d.p.i) and successful virus isolation from eye at 3rd and 7th d.p.i, from nose at 3rd d.p.i from rectum at 3rd, and 9th d.p.i, whereas plasma and Buffy coat were found to be positive till 5th d.p.i and sera till 11th d.p.i, meanwhile the antibody response increased from the 6th and 7th d.p.i till the end of experiment. Group Π revealed increase body temperature at 3rd and 4th d.p.i and RVF virus disappeared from eye, nose, and rectum, but successful virus isolation from blood continued until the 3rd and 4th d.p.i, moreover the antibody response appear at the 4th and 5th d.p.i and continued to increase with higher values than group I till the end of experiment. Group ΙΙΙ exposed normal body temperature without virus shedding or antibodies in their sera. In conclusion Smithburn strain can be used as attenuated vaccine or a seed for production of inactivated vaccine as it was more immunogenic than ZH501 strain