In this contribution the effect of alkaline-earth (AE) dopants Mg2+, Ca2+, Sr2+ and Ba2+ on sinterability and functional response of KNN is studied. Ceramic powders with the general formula (K0.5Na0.5)(1-2y)AE(y)NbO(3), y= 0.005 were prepared by classical ceramic processing. The values of 94-95% of theoretical density (TD) are obtained for stoichiometric KNN after sintering at 1115 degrees C for 2 h. Calcium and strontium doping promotes densification while magnesium doping inhibits it. In the case of Ba-doping a secondary phase forms. The dielectric constant and piezo d(33) coefficient determined by Berlincourt piezo d(33)-meter of Ca and Sr-doped KNN ceramics are 500 and 95 pC/N, respectively, while the values for undoped KNN are slightly lower. (c) 2005 Elsevier Ltd. All rights reserved.