Inclusive studies were conducted to estimate the humoral immune response of balady and marino sheep post vaccination with inactivated Rift Valley Fever (RVF) vaccine, firstly the safety test in lambs and the potency test in mice were done. The specific developed RVF antibodies were monitored for six monthes by both serum neutralization test (SNT) and enzyme linked immunosorbant assay (ELISA). The studies indicated that the balady sheep is earlier to respond than marino sheep. Hence it could be used efficiently for evaluation of the produced inactivated RVF Vaccine,