The electrokinetic behavior of BaTO3 particles in an aqueous medium exhibited a hysteresis loop with titration direction. As BaTiO3 suspension was titrated toward acidic pH, the amount of Ba2+ dissolution strongly increased, and in the subsequent titration toward alkaline pH, Ba2+ adsorbed and/or reprecipitated on the Ba-depleted BaTiO3 surface. This dissolution-reprecipitation cycle results in the observed hysteresis behavior. An attempt was made to identify the responsible species of the adsorbed/reprecipitated compound by XPS in conjunction with electrokinetic titrations. (C) 2002 Elsevier Science Ltd. All rights reserved.