Rift Valley Fever (RVF) is an endemic disease in Egypt causing disease in animals and humans since the 1977. Full molecular description of the national vaccine strain is a strategic concern to ensure the antigenic makeup of local vaccine is adequate to provide the required protective immunity for the vaccinated animal species and as a tool of final product quality control. Molecular characterization and phylogenetic analysis of Gc gene of M segment of RVF-ZH501 strain which used in local vaccine production in veterinary serum and vaccine research institute (VSVRI) were carried out in this study. RVF-ZH501 strain was propagated by passages on BHK cell line and then purified my plaque purification technique. RT-PCR for amplification of the Gc gene of M segment. Sequence analysis of the obtained PCR product carried out by MEGA7 program. The result of the study revealed that RVF strain ZH501 Gc genomic content has 99.5 % molecular identity to the strains firstly isolated in Egypt in 1977, so still suitable for vaccine production.