The gamma irradiation-induced degradation of Reactive Blue-19 (RB-19) as a model system in aqueous media has been evaluated. The process variables such as dye initial concentration (50–150 ppm), H2O2 concentration (0.1–0.9 ml) and gamma radiation absorbed dose (1–12 kGy) were optimized to get maximum degradation. The efficiency of AOP was assessed on the basis of degradation, reduction in COD/BOD and toxicity of the dye. A complete degradation and 60% removal in COD/BOD were obtained at H2O2 (0.9 ml) under the gamma radiation absorbed dose of 12 kGy. The UV/Vis spectrophotometer was used to investigate the change in absorbance before and after irradiation. The radiolytic progress and degraded end-products of the treated samples were determined by comparing the before and after irradiation dye spectra of FT-IR. The results of FTIR spectra showed that the anthraquinone structures, nitrogen linkages and amino groups of RB-19 were destroyed under gamma irradiation. The identification by LC-MS analyses indicated that some organic acids (e.g. phthalic acid) could be the primary degradation products. The hemolytic test showed 19.30% hemolysis, while gamma/H2O2 treatment reduced mutagenicity up to 89.7% and 97.91% against TA98 and TA100 bacterial strains, respectively. The study showed that the gamma radiation based advanced oxidation process can be favorable and probably be used for the remediation of dyes waste-water having toxic dyes.