Purpose -To explore the effect of acrylic acid polymerization and NaOH treatment of nylon-6 on hemoglobin washability. Design/methodology/approach -The nylon-6 was chemically grafted with acrylic acid and treated with NaOH for the purpose to improve the washability of hemoglobin as a blood protein soil. The structural change before and after graft polymerization was analyzed by X-ray photoelectron spectroscopy and scanning electron microscopy. The moisture regain, the contact angle, and the washability were each measured. Findings -Graft polymerization and NaOH treatment of nylon-6 changed the surface energy and structure of nylon-6 causing the washability of hemoglobin to improve. Compared to ungrafted nylon-6, the hydrophilic properties were increased remarkable by graft polymerization and NaOH treatment, which reulted in the improvement of washability. Practical implications -Hemoglobin is one of the most difficult soils to remove from the fabric. The paper might be of interest to those who would consider purchasing fabrics that are good at both hydrophilic properties and washability. Originality/value -The study on washability of hemoglobin as a blood protein soil for grafted fabric has not been reported so far. The results of this research may be used in a basic research for the development of new process which is capable of improving of hemoglobin washability.