Aim:To design, synthesize and characterize a new series of 7-(4-((substituted)5-thioxo-4.5-di hydro-1,3A-oxadiazol-2-0) methyl)-4-(phenylamino)-9(trichloromethyI)-1-thia-4,7,5-triazaspiro[4.4]non-5-ene-3,6-di one and evaluate for antimicrobial activity. Material and Method: All title compounds were structurally elucidated on the basis of spectroscopic and elemental analysis. The antimicrobial screening was carried out by employing cup plate method. The zone of inhibition (mm) of each compound was determined and compared with that of standard drug. Results: The relationship between the substituent group and the biological activity of the compounds was discussed. Discussion: While all the compounds exhibited moderate antibacterial activity, Vila, Vllb and Vllc were found to be better antibacterial agents and VIld, Vile and Vhf were found to be superior antifungal agents than the other title compounds.