This paper summarizes the distribution of iron oxides in red and forest soils of Taiwan, using the high gradient magnetic separation (HGMS) technique. Soil iron oxides were measured by the methods including wet chemistry, X-ray diffraction (XRD), magnetic measurement, transmission electron microscope (TEM) and electron diffraction, Fe-57 Mossbauer analysis, etc. Acidic red soils developed from andesitic rocks of Ta-Tun, and Lu-Tau, Lau-Hsu and Peng-Hu calcareous red soils developed from basaltic rocks showed high magnetic susceptibility and contained ferrimagnetic minerals of magnetite or maghemite. Goethite and/or hematite could be identified in the most red soils. The clays accumulated in B horizons of the Shou-Ka soils and podzols occurring on high mountains were found to contain lepidocrocite. Magnetic clay fractions of Shou-Ka soils characterized by XRD and Fe-57 Mossbauer analysis showed that Shou- Ka soils contained goethite, lepidocrocite, poor crystalline hematite and iron-rich chlorite. Structural Fe²⁺ in iron-rich chlorite was located at talc-like cis-OH (M2) sites. The observations of TEM and electron diffraction of forest soils showed that goethite was lath-shape and indexed as(100) plane.