The radiolysis of ibuprofen(IBP),a model pharmaceutical compound,was studied by gamma irradiation in anaqueous solution in the presence and absence of potassium persulfate(K₂S₂O₈). The extent of mineralization was investigated by measuring the UV–visible spectra,decrease in the chemical oxygen demand (COD) and the total organic carbon (TOC)content of aqueous IBP solution at different doses.The gamma radiolysis,in the presence of K₂S₂O₈, required much lesser dose compared to in the absence of K₂S₂O₈ for the same extent of mineralization of aqueous IBP solution.The pulse radiolysis of IBP was carried out under different radiolytic conditions to understand the mechanism of efficient mineralization of IBP during gamma radiolysis in the presence of K₂S₂O₈. It was found that unlike • dOH radical,SO4•^- radical preferentially produces benzyl type of radicals via the formation of the benzene radicalcation. The results concluded that the gamma radiolysis in presence of K₂S₂O₈ could be one of the efficient advanced oxidation processes for degradation of pharmaceutical compounds present in the aqueous solution.