In order to improve the efficiency of sulfidization methods for oxidized ores, the problem of reducing the energy intensity of the process must be solved. In this regard, a promising method is the sulfidization of oxidized copper ores using a modified reagent that allows the process to be conducted without heating or any separate equipment. The modified sulfidizing agent designed to improve the efficiency of flotation concentration is produced by the mixing of sodium polysulfide and ammonium sulfate solutions. Comparative flotation experiments were conducted using pre-sulfidized oxidized copper ore containing 1.2 % of total copper, of which 1.08 % (or 90 %) was oxidized copper. The possibility of carrying out the sulfidization process in a flotation cell without forced heating of the reaction mixture has been established. At the same time, the modified reagent exceeds sodium polysulfide in terms of its flotation efficiency by 5 %. The chemical analysis of the processing products for the content of oxidized copper has demonstrated that its mass fraction decreased from 1.08 to 0.63 %. The experimental design method has been used to establish the best application conditions for the modified reagent. These are: the reagent consumption of 2.6 kg/t; slurry agitation with the sulfidizing agent for four minutes; and the collector (potassium butyl xanthate) consumption for the flotation process of 500 g/t. The copper recovery was 69.85 %. A mathematical model was designed for the flotation process with preliminary sulfidization of the oxidized copper ore in the form of a generalized miltifactorial equation.The work was performed with the grant support of the Ministry of Education and Science of the Republic of Kazakhstan (grant No. AP05130143).