This paper reports the temperature and concentration dependence of anisotropic etching of (100) silicon in aqueous KOH solution. Etching rate of wet etching of (100) silicon in pure KOH solution has been experimentally determined with varying KOH concentration and the temperature of the KOH solution. Atomic force microscopy (AFM) and optical microscopy have been employed for the inspection of the quality of the etched surfaces. It has been observed that the etching rate increases with increasing temperature of the KOH solution for concentrations varying from 10% to 45% by weight. However, for a given KOH temperature, the etching rate decreases with increasing KOH concentration. The 10% KOH solution in contrary enhances oxidation of the silicon surfaces leading towards more hydrophilic and therefore a reduced etching rate is resulted.