Hematite (α-Fe2O3) nanowires have been synthesized on a large surface area by thermal oxidation of iron foil in an ozone-rich environment. The effects of annealing time, temperature, and oxidizing environment on the growth of nanowires have been systematically studied. The samples were characterized using scanning electron microscope (SEM), transmission electron microscope (TEM), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS). It was found that annealing in ozone-rich environment for 2–4 h at 700 °C yielded the best results in terms of number density and diameter of nanowires. The average diameter of the nanowires was found to be 85 nm. It was found that nanowires are bicrystal in nature with a length around 4 μm, which grows uniquely along the  direction.