The removal of cyanides from water by catalytic air oxidation was studied. Experiments were separately performed in a fixed bed reactor with co- and counter-current flow. Effects of concentration, flow type, liquid and gas flow rates on oxidation yield were investigated. It was consequently observed that the yield was increased with decreasing gas flow rate. The yields attained at countercurrent conditions were higher than those of cocurrent ones. The yield was not significantly affected by the change in concentration and liquid flow rate. The reaction was found to be of zero-order,with respect to cyanide in water. Although this study was carried out at a continuously operating system, a yield of 99% was achieved at low gas flow rates and countercurrent conditions. (C) 2002 Elsevier Science B.V. All rights reserved.