Pigment dispersion in water-reducible paints was discussed from the view points of wetting and stabilization. Stabilization was attained by resin adsorption on the pigment surface and the DLVO theory was not applicable to the actual paint systems. Hydrophobic and electrostatic interactions were the major driving forces of resin adsorption. Using the most suitable pigment surface hydrophobicity level, both wetting to the aqueous medium and stabilization by resin adsorption through a hydrophobic interaction were adequately attained. An amphoteric resin showed excellent pigment dispersibility due to an attractive electrostatic interaction between the resin and the pigments. In this case, considerations of pigment charge, acid/base strength of the resin and neutralizing amines or acids, were necessary. Finally a structural effect of pigment clustering on wetting was elucidated.