Wu¨stite pellets were reduced to iron in H₂, CO, and CO·CO₂mixture under a total pressure of 765 mmHg at temperatures ranging from 650℃ to 1,050℃. The reduction rates were calculated by the decrease in weight of samples during reaction. The diffusion rates of iron through wu¨stite layer were observed by means of microscopic examination as well as chemical analysis. Relationship between solid state diffusion and overall reduction rates was examined to find out the rate controlling step. The mechanism and kinetics are discussed and activation energy are also calculated.