Nylon fabric was grafted to improve detergency against hemoglobin, a protein soil. With free-radical chemical initiator systems, the grafting of acrylic acid(AA) as a hydrophilic vinyl monomer was performed to change surface free energies. Ammonium persulfate(APS) was used as an initiator and acrylic acid grafted nylon was treated with NaOH solution. The properties of the nylon, such as water uptake and the hemoglobin removal rate, were investigated. The water uptake of nylon increased after grafting and alkaline treatment. Hemoglobin was easily removed from grafted nylon, while it was difficult to remove hemoglobin from ungrafted nylon. The detergency of hemoglobin for grafted nylon decreased when the graft ratio exceeded 15%. The detergency of hemoglobin increased markedly with increasing washing time and washing temperature. The removal of hemoglobin was found to fit well to a first order reaction of time. The rate constant of hemoglobin removal for 5% nylon-g-NaAA is larger than that for ungrafted nylon. It means that the detergency of hemoglobin was improved due to grafting and alkaline treatment.