The influence of polyacrylic acid (MW 2000-10 000) on the stability of TiO2 dispersions is investigated both in dilute suspensions (by light transmission) and in concentrated dispersions (by rheology). Polyacrylic acid in low concentrations destabilizes TiO2 dispersions, but at higher concentrations a stabilizing influence is found. In the high-concentration region, especially stable dispersions can be obtained when electrostatic and steric stabilization act simultaneously.