A series of new 5-(2,6-dichlorobenzylidene)thiazolidine-2,4-dione and 5-(4-methoxybenzylidene)thiazolidine-2,4-dione derivatives (3a-h and 5a-h, respectively) were synthesized starting from 5-arylidenethiazolidine--2,4-dione and α-halo-ketones. The structural elucidation of the newly synthesized compounds was based on elemental analysis and spectroscopic data (MS, 1 H-NMR and 13 C-NMR). The synthesized compounds were screened in vitro for their antimicrobial activities against several pathogenic strains of Gram-positive and Gram-negative bacteria and one fungal strain (Candida albicans), as growth inhibition diameters. Some of the compounds displayed better inhibitory activities than that of the reference drug against the Gram--positive Staphylococcus aureus, Bacillus cereus and Listeria monocytogenes bacterial strains, and showed good antifungal activity against C. albicans, while the antibacterial activity against the Gram-negative Escherichia coli and Salmonella typhimurium bacterial strains was moderate.