To obtain silk weight gain and to improve silk properties, Bombyx mori silks were grafted with either 2-hydroxyethyl methacrylate (HEMA) or methyl methacrylate (MMA). The moisture regain of the HEMA-grafted and MMA-grafted silks depended on the hydrophilicity of the used monomers. The acid and alkaline resistances of the HEMA-grafted and MMA-grafted silks were clearly improved. Both commercial synthetic dyes, that is, acid and reactive dyes, and a natural dye extracted from turmeric, with potassium aluminum sulfate as a mordant, were used in this study. The results suggested that the dye uptake increased in the presence of poly(2-hydroxyethyl methacrylate) or poly(methyl methacrylate) in the silk fibroin structures when acid and curcumin dyes were used. The wash-fastness level of the HEMA-grafted silk dyed by acid and reactive dyes was similar to that of the degummed silk. However, the colorfastness to washing of the MMA-grafted silk dyed by an acid dye was improved when the polymer add-on concentration was 65%. In addition, the washfastness for both grafted silks was improved when they were dyed with natural curcumin dyestuff. The acid and alkaline perspiration fastness properties remained unchanged for the HEMA-grafted and MMA-grafted silks when acid, reactive, and curcumin dyes were applied. (C) 2007 Wiley Periodicals, Inc.