Blends of polypropylene (PP) and modified atactic polystyrene (PS) with good processability were studied for dyeable fine and superfine fibers. Acrylic acid and butyl acrylate monomers were added to PS by radical suspension copolymerization. The dispersion of the additives in the PP crystal was investigated. The rheology curves of the blends were similar to that of PP tinder the testing conditions. Fine and superfine PP filaments were processed from these blends, and they had practical mechanical properties. The dyeability of the fabrics from the fibers was studied. The increased amorphous content and the interface between PP and modified PS allowed the dyes to penetrate the fibers. These two effects helped to improve the color intensity. The color fastness was also improved by the presence of polar groups introduced by the modified PS components. (c) 2005 Wiley Periodicals, Inc.