The decolorization of Reactive blue 28 (RB 28) in aqueous solution has been studied using Fenton (Fe 2+ /H 2 O 2 ) and photo-Fenton (Fe 2+ /H 2 O 2 /UV) processes. This investigation indicates that both these methods can remove the color of RB 28. The e ffects of different system variables namely initial concentration of Fe 2+ , initial concentration of H 2 O 2 , initial pH of solution and initial dye concentration were studied. The increase of initial dye concentra tion decreases the decolorization rate. Under optimum conditions, the photo-Fenton process was found to be more efficient than Fenton process.