In attempt to find new pharmacologically active molecules, we report here the synthesis and in vitro antimicrobial activity of various 3-(1,3,4-oxadiazol-2-yl)-quinazolin-4(3H)-ones. The antimicrobial activity of title compounds were examined against two gram positive bacteria (S. aureus, S. pyogenes), two gram negative bacteria (E. coli, P. aeruginosa) and three fungi (C. albicans, A. niger, A. clavatus) using the broth microdilution method. Some derivatives bearing a bromo or iodo group exhibited very good antimicrobial activity.