Abstract: Process for dyeing evenly synthetic fiber materials and mixtures thereof with natural fibers, with water-insoluble disperse dyestuffs according to the exhaust method, which comprises adding water-soluble or dispersible linear polyesters that have been obtained by polycondensation of dicarboxylic acids with diols, including sulfo-groups-containing chain links, with an average molecular weight of 800 to 5,000, combined with surface-active oxethylation products, at a blend ratio of 1:0.25 to 1:1.5, as dispersing system with levelling action to the aqueous dyeliquors, besides said dyestuffs and pH-controlling substances.