Three hydroxyapatite powders with different surface properties were produced by wet-chemical synthesis and characterized. The electrokinetic properties of powders dispersed in water were investigated by electroacoustic spectroscopy measurements. The different surface reactivity (pH(iep) and zeta potential versus pH curves) was related to the interplay of dissolution and adsorption of Ca2+ ions. With a view toward the preparation of porous bodies by sponge impregnation, the behavior of powder suspensions was studied. Four deflocculants. were tested, and the optimum dispersing conditions for each powder were found. Anionic polyelectrolytes resulted in the best effective dispersing agent, with different optimum amounts added to the suspensions.