Dyeing properties of three sulfadiazine type reactive dyes (Re-Red, Re-Blue1, and Re-Blue2) synthesized newly from (silver) sulfadiazine, H-acid, and p-base were evaluated by dyeing cotton fabric with them. The synthesized reactive dyes showed somewhat lower build-up property and lower exhaustion ratio compared to those of a commercial dye. The fastness to light, washing, and crocking of the dyed cotton fabrics showed fairly good grade. However, the antimicrobial activities of the dyed fabrics tested using Staphylococcus aureus (AT.C.C. 6538) as a cultivating bacterium were excellent. The dyed fabrics also showed very good durability of the antibacterial activities to repeated launderings. Re-Blue1 synthesized from sulfadiazine is more effective than Re-Blue2 synthesized from silver sulfadiazine considering the manufacturing cost and antibacterial activity of the dyed fabric.