A series of novel 3-[5-substituted phenyl-1,3,4-thiadiazole-2-yl]-2-styryl quinazoline-4(3H)-ones were synthesized and evaluated for antibacterial activity against pathogenic strains of Staphylococcus aureus (MTCC no. 96), Bacillus subtilis (MTCC no. 619), Pseudomonas aeruginosa (MTCC no. 424) and Escherichia coli (MTCC no. 40) and antifungal activity against Aspergillus niger, Candida albicans and Fusarium oxysporum. The cup-plate method was employed to determine the minimum inhibitory concentration (MIC) value of the compounds. Some of the compounds exhibited activity comparable to Norfloxacin. The present report reveals that synthesized 2-styryl-quinazoline-4(3H)-one exhibited better antibacterial than antifungal activity.