Bioeffect of some Syrian Myrtus communis L. leaves extracts in growth of some pathogenic microorganisms, which were isolated from Al-Assad hospital laboratory in Lattakia, was tested by disc diffusion method. Results showed that cold and hot water extracts have antibacterial activity against all Gram positive and negative bacteria, and pathogenic Candida albicans except Klebsiella pneumoniae. All organic extracts have antibacterial activity against Proteus vulgaris, Entrococcus faecium, Staphylococcus aureus and Staphylococcus albus. Pseudomonas aeruginosa and Pseudomonas fluorescens were affected by most of the organic extracts, and the most bioactivity was by methanol extract, and all inhibition zones of extracts were bigger than inhibition zones by control antibiotics. Serratia marcescens and Acinetobacter calcoaceticus were affected by methanol (with highest inhibition zone 37.33 and 27.33 mm respectively), ethanol, acetone and ethyl acetate extracts, but resistant to the others. Klebsiella pneumoniae affected by ethanol extract only with inhibition zone 20.33 mm. Results of bioactivity according to a various solvents used in this study demonstrate that Syrian Myrtus communis L. leaves extracts have antimicrobial activity, so expected to be potential sources of natural antibacterial and antifungal products against some pathogenic bacteria and fungi in the future.