3D QSAR analysis for the 21 molecules of 1,3,4-oxadiazoles was carried out by using k-Nearest Neighbor Molecular Field Analysis (kNN-MFA) combined with various selection procedures. 30 3D QSAR models were generated; one of these models was selected on the basis of q(2) and pred_r(2) values. The selected Model has training set of 17 molecules and test set of 4 molecules with validation (q(2)) and cross validation (pred_r(2)) values of 0.6969 and 0.6148 respectively. Title compounds of 1,3,4-oxadiazole derivatives were synthesized by the ring closure reactions of various acylhydrazides with carbon disulphide (4a-e) and with aromatic acids in POCl(3) (5a-e). After structural elucidation, all the synthesized compounds were evaluated for their antimicrobial activity against Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis.