A new series of (s)-1- {3-[4-(4-benzo[d]isothiazol-3-yl-piperazin-1-yl)-3-fluorophenyl]-2-oxo-oxazolidin-5-ylmetyl}-3-substituted-urea derivatives have been synthesized and characterized with spectral data, such as IR, NMR and Mass spectroscopies. All compounds are in vitro evaluated for their efficacy as antimicrobial agent against the gram-positive pathogenic strains such as Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228 and Streptococcus pyogens ATCC 8668. Five compounds (19k, 19l, 19m, 19n and 19o) out of 15 compounds showed moderate activity.