Abstract: Brass ash from the industrial brass manufacturer in Turkey was leached using the solutions of ionic liquid (IL) 1-butyl-3-methyl-imidazolium hydrogen sulfate (bmimHSO₄) at ambient pressure in the presence of hydrogen peroxide (H₂O₂) and potassium peroxymonosulfate (oxone) as the oxidants. Parameters affecting leaching efficiency, such as dissolution time, IL concentration, and oxidizing agent addition, were investigated. The results show that bmimHSO₄ is an efficient IL for the brass ash leaching, providing the dissolution efficiencies of 99% for Zn and 24.82% for Cu at a concentration of 50vol% bmimHSO₄ in the aqueous solution without any oxidant. However, more than 99% of zinc and 82% of copper are leached by the addition of 50vol% H₂O₂ to the bmimHSO₄ solution. Nevertheless, the oxone does not show the promising oxidant behavior in leaching using bmimHSO₄.