This book deals with the synthesis of some substituted benzaldoximes from their corresponding benzaldehydes by the reaction of the alcoholic solution of these benzaldehydes with hydroxylamine in the presence of sodium hydroxide (NaOH) using ethanol/water solution as solvent medium. Structural elucidation of the synthesized compounds was carried out by infrared spectroscopy (IR) and Gas chromatography-Mass spectroscopy (GC-MS) analysis and the predicted structures is in agreement with spectral data obtained. The study revealed that this synthetic route produces bezaldoximes of good yields (74- 79%). The synthesized compounds (5a-d) were subjected further to screening for their antimicrobial ability against two Gram-positive bacteria (Bacillus subtilis strain AIMST 2ME11 and Bacillus cereus strain CF7) and three Gramnegative bacteria (Pseudomonas acruginosa strain PG1 and Pseudomonas aeruginosa Strain 333K35 and Eschericha coli). Their zones of inhibition were measured and it was revealed that compound 5a has no antibacterial ability against all five bacteria isolates tested against.