Photocatalytic degradation of methylene blue over ferric tungstate in presence of light has been carried out. The progress of the reaction was monitored spectrophotometrically. The effect of some parameters affecting the rate of reaction, such as pH, dye concentration, amount of semiconductor, light intensity, etc. has been studied. Kinetic studies show that this reaction follows pseudo-first order kinetics. A tentative mechanism for photocatalytic degradation of methylene blue has also been proposed.