1,3,4 oxadiazole derivatives are the heterocyclic compounds with very important biological activities such as anti-inflammatory, antimicrobial, antifungal, antiviral, analgesic, antimycobacterial, antidepressant and antiamoebic. 1, 3, 4 oxadiazole was synthesized by condensation reaction between 2- hydroxybenzohydrazine and carbon disulfide. This derivative on treatment with different aromatic halides produced the desired final products. The in-vitro antibacterial activity of synthesized compound was tested against Gram-positive and Gram-negative microorganisms (Staphylococcus aureus ATCC 9144, Bacillus subtilis ATCC 6633, Pseudomonas aeruginosa MTCC No. 1688, Gram negative: Escherichia coli ATCC 25922) by filter paper disc method. The in-vitro antifungal activity was tested against Candida albicans by filter paper disc method. All the compounds showed good activity against all cultures.