Vaccination is considered the most effective measure to control lumpy skin disease, Various types of Capripoxvirus vaccine strains are used in vaccination programs. In Egypt, since the appearance of LSD in 1988, various live attenuated sheep pox vaccines were used. The aim of this study was preparation and evaluation of a new live attenuated tissue culture trivalent vaccine from two sheep pox viruses (Romanian, Kenyan sheep pox) and one goat pox viruses (Held goat pox virus) as a trial to improve vaccination against LSD. Capripox viruses were titrated in Vero cell, and were mixed with each other in equal volumes (1:1:1) with equal titers (4.5log₁₀TCID₅₀/ml). The experiment was performed using 24 calves of 6-12 months, They were divided into three groups; the first group of 12 animals were vaccinated with the new trivalent vaccine, second group of 12 animals were vaccinated with monovalent Romanian sheep pox vaccine and the third group of animals were left as non-inoculated contact controls. The cellular immunity of all animals were estimated using lymphocyte blastogenesis measured by XTT assay and the humoral immunity were evaluated by serum neutralization test and ELISA. The results revealed that the trivalent vaccine showed higher level of cellular immunity for longer perioed as compared to the monovalent Romanian sheep pox vaccine. The level of antibodies measured by SNT and ELISA was protective in animals vaccinated with both vaccines. Challenge test was applied using 0.5 ml of virulent LSDV (5log₁₀TCID₅₀/ml) every 3 months till the end of experiment (12 months post inoculation). The trivalent vaccine was protective in 100%, 100% , 66% of vaccinated animals at, 6, 9,12 months post vaccination respectively, while the potency of Romanian Sheep Pox Vaccine was 100%, 100%, 33% at the same periods No  post vaccinal reaction appeared on all  vaccinated animals . In conclusion the current study proved that a trivalent vaccine (Romanian, Kenyan sheep pox and goat pox viruses) was safe, potent, high immunogenic and provide long duration of immunity.