Copper loaded hydroxyapatite prepared by ion exchange were characterized by XRD, FTIR, BET, UV-vis, H(2)-TPR and evaluated in the selective catalytic reduction of NO by NH(3) under oxidizing atmosphere. The Cu-Hap catalysts, without the libethenite phase presence, have been found to be active, and selective in the NH(3)-SCR process. The highly dispersed CuO clusters on Ca-Hap surfaces were responsible for the NO conversion in the low temperature range in the NO-SCR with NH(3). The presence of 2.5% of H(2)O in the feed mixture strongly affects the NO conversion in the whole temperature range. (C) 2011 Elsevier B.V. All rights reserved.