The decolorization of Reactive blue 28 (RB 28) in aqueous solution has been studied using Fenton (Fe2+/H2O2) and photo-Fenton (Fe2+/H2O2/UV) processes. This investigation indicates that both these methods can remove the color of RB 28. The effects of different system variables namely initial concentration of Fe2+, initial concentration of H2O2, initial pH of solution and initial dye concentration were studied. The increase of initial dye concentration decreases the decolorization rate. Under optimum conditions, the photo-Fenton process was found to be more efficient than Fenton process.