Honey and Royal Jelly are complex heterogeneous mixtures of flowers" nectar sugars proteins and bees" glandular secretions. Royal Jelly is the hypo-pharyngeal gland excretion of the young worker honeybees (Apis mellifera). The wonderful effects of Royal Jelly on the sexual ability and maturity of the queen has been an interesting topic and controversial issue for researchers for many years. The main purpose of this study was to investigate the anti-bacterial effects of Royal Jelly against six different bacteria (Escherichia coli, Staphylococcus aureus, Streptomyces griseus, and three unclassified strains of Streptomyces). Four concentrations of water soluble extracts of pure Royal Jelly were prepared and added drop wise to the bacterial strains seed layer cultured individually. Attempt was made to find out the antibacterial properties of Royal Jelly by means of agar distribution method (drop-plate). The diameter of the clean zone formed in each concentration was measured and correlated to the ability of the extracts to inhibit the growth of microorganisms. Interestingly the results show inhibitory effects of Royal Jelly on different strains of the bacteria in-vitro. Ethersoluble and non-soluble fractions of the Royal Jelly were also examined using the above method. It was found that the antibacterial effect of ether-soluble fraction is substantially higher than the effect of ether non-soluble fraction. The zones formed by ether-soluble fractions of Royal Jelly in the rout of distribution in agar belong to the potency of anti-bacterial properties of fatty acids present in this fraction of Royal Jelly (10 -HDA). It was also shown that the non ether-soluble fraction of Royal Jelly contains a bactericidal substance called Royalisin that was found to have potent antibacterial activity. This fraction of Royal Jelly revealed weaker anti-bacterial effect than the ether-soluble fraction and even of pure Royal Jelly.