A series of 3-acetyl-2-aryl-5-[2-(aryloxymethyl)phenyl]-2,3-dihydro-[1,3,4]-oxadiazoles (4a-p) have been synthesized and evaluated for their antimicrobial activity. Initially, the acid hydrazides (2a-d) derived from 2-(aryloxymethyl) benzoic acids (1a-d) were reacted with various aromatic aldehydes to yield hydrazones (3a-p). Further reaction of these hydrazones with acetic anhydride afforded the title compounds. All structures of the new compounds were established on the basis of their elemental analyses, IR, 1H NMR, 13C NMR and mass spectral data. The newly synthesized compounds were evaluated for their antimicrobial activities. Preliminary results indicated that some of them exhibit promising activities and they deserve more consideration as potential antimicrobial agents.