A series of novel [1,2,4]triazolo[4,3-a]quinoxalinone derivatives have been synthesized. The structures of the newly synthesized compounds were confirmed by elemental analysis and different spectral techniques. The in vitro antimicrobial screening of some selected compounds was carried out using the diffusion agar technique. Compound 14_c was found to be the most active antibacterial agent against Escherichia coli using gentamicin as reference drug. All the tested compounds showed no activity against Candida albicans  and Pseudomonas aerugeosa.