Abstract: Low density, porous, metal oxide microspheres are prepared from metal salt solutions by sol-gel technique followed by ammonia treatment of the green microspheres, drying, impregnation with fugitive organic material and heat temperature under controlled conditions of temperature and atmosphere. The product metal oxide microspheres have a density of below 70% of their theoretical maximum density and a porosity of at least 0.04 cubic centimeters per gram as measured by mercury penetration technique. Microspheres of hematite, magnetite, and other metal oxides useful as catalysts or as purifying agents to remove contaminants from liquid or gaseous streams may be produced.