The five member ring as 1,3,4 - thiadiazole and 1,3,4 - Oxadiazole bearing Schiff bases derivatives were prepared in our study by reacting the 1,3,4 - thiadiazole part with 1,3,4 - oxadiazole part in ethanol to produce 1,3,4 - oxadiazole hydrazinyl - 1,3,4 - thiadiazole, which were treated with aromatic aldehyde to produce of 1,3,4 - thiadiazole hydrazinyl 1,3,4 - oxadiazole bearing Schiff base. The structures of synthesized compound have been identified on the principles of their mass, 1H - NMR, Ft - IR, Mass spectrum and C, H, N elemental analysis. The synthesized compounds which founded have a strong antimicrobial activity, were assessed to their antibacterial activity by inhibition the growth of 3 strains of Gram negative bacteria Pseudomonas auerogenosia, Escherichia coli and one strain which produce enzyme called extended spectrum Beta lactemse (ESBLs) and 2 strains of Gram positive bacteria such as Bacillus cereus and Staphylococcus aureus.