Dyes released from industrial textile processing constitute major problems into the environment. In the present work, ionizing radiation such as electron beam irradiation was utilized in the decoloration and degradation of the remained dye waste after dyeing cotton fabrics with four different dyestuffs based on azo and anthraquinone structures. The treatment of the remained dye waste was also carried out by gamma irradiation for comparison. The influences of irradiation dose, H2O2 concentration, pH of the solution, and dye concentration on the percentage decoloration was studied. In addition, the chemical oxygen demand (COD) and total organic carbon contents (TOC) were described. The results showed that the higher decoloration and degradation of dyes was obtained in case of using electron beam than gamma irradiation at the same conditions. The TOC and COD reduction for all dye solution were approximately 72-91% and 71-93% respectively. (C) 2011 Elsevier B.V. All rights reserved.