Spent Pd-activated carbon catalyst used for redn. of org. compds. with H was studied. The catalyst samples were oxidized with 7.5% H2O2, heat-treated in vacuum (2 h at 472 K, then 2 h at 673 K), heated in micro-wave reactor (10 min at 448-453 K) and reduced with H at 413 K. The regenerated catalyst samples were then used in a test hydrogenation of octanoylbenzene to det. their activity. The conversion degree was 73-89% compared with 99.5% achieved for the fresh com. catalyst and the catalysts formerly regenerated with supercrit. CO2. XPS and XRD techniques were used to assess the changes in the state of the Pd present on the catalyst surface taking place during the regeneration.