Aqueous pigment slurries which contain up to 80% by weight of a finely divided pigment in dispersed form and from 0.1 to 5% by weight of dispersants which are obtainable by reacting (a) polyalkylenepolyamines, polyamidoamines, polyamidoamines grafted with ethyleneimine, polyetheramines and mixtures of the stated compounds and (b) monoethylenically unsaturated carboxylic acids, salts, esters, amides or nitriles of monoethylenically unsaturated carboxylic acids, chlorocarboxylic acids and/or glycidyl compounds and, if required, (c) bifunctional or polyfunctional crosslinking agents which have a halohydrin, glycidyl, aziridine or isocyanate unit or a halogen atom as a functional group, to give water-soluble condensates which, in 20% strength by weight aqueous solution at 20.degree. C., have a viscosity of at least 100 mPa.s are prepared by milling or dispersing pigments in the presence of the dispersants and water and are used as additives to paper stock in the production of filler-containing paper.