The present study aimed to investigate the efficiency of nanotechnology in bleaching three important used Egyptian oils (soybean, corn and sunflower). The raw bleaching earth powder was milled for 10 h in a planetary ball mill. X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM) were used to investigate morphology, crystallite size, lattice strain and particle size of as-received and milled powders. The mechanical alloying process succeeded to obtain nano-sized bleaching earth powders after 10 h of milling and the morphology appeared rod with 46.6 nm in length and 4.46 nm in diameter. The milled nano-sized bleaching powder was used in bleaching of oils under study. Comparing color indices, peroxide values and spectral absorbencies at 232, 270 nm for the resulted bleached oils with the unbleached and control ones bleached with raw bleaching earth, it was concluded the high bleaching efficiency of nano-sized bleaching earth in reducing color indices, peroxide values and spectral absorbencies at 232, 270 nm.