Synthesis of benzamido carboxylic acid [1-5]:- Condensation of appropriate amino acid (p- amino benzoic acid, o- amino benzoic acid, valine, leucine, phenyl alanin) with benzoyl chloride gave the corresponding benzamido carboxylic. The Synthesis of 2,5-disubstituted-1,3,4-oxadiazoles [6-10] Reaction of appropriate benzamido carboxlic acid with benzoyl hydrazine in the presence of phosphorous oxychloride furnished the corresponding 2,5-disubstituted 1,3,4-oxadiazoles [6-10]biological activity of the synthesized compounds [1-10] for their antimicrobial activity against two strains of pathogenic microorganism Gram positive bacteria Staphylococcus aureus and Gram negative bacteria Escherichia coli. Antifungal activity were also evaluated against Trichophytone rubrum. And finally, the cytotoxic effect were evaluated in normal cell line (Mouse embryo fibroblast) after 72 hrs of incubation. The results obtained revealed that all compounds showed measurable activity against the two type of bacteria using two concentration (0.005g/5ml ) and (0.008g/5ml).