Copper bearing 13X zeolite was prepared from commercial 13X zeolite via ion-exchange with copper acetate solutions. After the incorporation of copper, Cu/13X catalyst was exposed to post synthesis thermal treatment at different temperatures. The prepared catalysts were characterized by XRD and FTIR, while the adsorption techniques were used for the measurement of the specific surface area and pore volume. The catalytic tests were carried out in a stainless steel Parr reactor in batch operation mode at atmospheric pressure in temperature range from 333 to 353 K. Influence of postsynthesis thermal treatment and reaction temperature on activity and stability of prepared catalysts in the catalytic wet oxidation process with hydrogen peroxide as oxidant was investigated. The experimental results showed that total degradation of phenol can be achieved under mild operating conditions at temperatures bellow 353 K. All catalysts exhibited higher activity in terms of hydrogen peroxide and phenol abatement with the increasing temperature of the reaction. The postsynthesis thermal treatment resulted in more stable catalyst with respect to stability of both catalysts active metal component (copper) and support, while the activity of catalysts in terms of TOC conversion remained unaltered.