The objective of this work was to study the suitability of catalytic wet air oxidation (CWAO) for the treatment of olive mill wastewater (OMW). Experiments were performed in a high pressure reactor at 100 and 200 degrees C under an oxygen partial pressure of 6.9 bar, using carbon supported platinum (1 wt.% Pt) and iridium (5 wt.% Ir) catalysts prepared by incipient wetness impregnation. At 100 degrees C, refractory organic compounds persisted even after prolonged reaction time (8 h). At 200 degrees C, complete total organic carbon and colour removal was obtained with the Pt/C catalyst after 8 h of reaction. A kinetic model was developed taking into account catalytic and non-catalytic reactions, formation of refractory compounds and catalyst deactivation. Very good agreement between the proposed model and CWAO experimental data at 200 degrees C was found. The results obtained in this work indicate that Pt/C is a promising catalyst for the CWAO of OMW. (C) 2007 Elsevier B.V. All rights reserved.