The photocatalytic activity of TiO2 and ZrO2-coated polyacrylonitrile (PAN) fibers was compared through the self-cleaning of methylene blue and eosin yellowish. TiO2 and ZrO2 nanocrystals were successfully synthesized and deposited onto PAN fibers with photocatalytic self-cleaning activity using the sol-gel process at low temperature. The pristine and treated samples have been characterized by several techniques, such as scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy, X-ray diffraction, and thermogravimetric analysis. The TiO2 nanoparticles with 10-20 nm in size, and ZrO2 with 20-40 nm have been synthesized to form dispersed particles on the fiber surface, which shows photocatalytic properties when exposed to UV-Vis light. The photocatalytic activity, tested by measuring the degradation of adsorbed methylene blue and Eosin Y. Photocatalytic activity of TiO2-coated fibers toward dyes degradation was higher than that of ZrO2-coated fibers. This preparation technique can be also applied to new fabrics to create self-cleaning and UV irradiation protection properties in them. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 2062-2070, 2010