The present invention relates to water soluble or water dispersible polyurethane elastomers which have a substantially linear molecular structure and which contain both ethylene oxide units incorporated in polyether chains and sulphonate groups, characterized in that they contain from about 0.5 to 20% by weight of ethylene oxide units of the formula --CH.sub.2 --CH.sub.2 --O-- arranged within polyether chains and from about 0.1 to 25 milliequivalents, per 100 g of solid, of sulphonate groups of the formula --SO.sub.3.sup..crclbar. in the form of structural units of the formula--O--X--Rarranged in end positions and/or side positions, whereinX represents a polyalkylene oxide chain having from 5 to 90 chain members, at least about 40% of which chain members constitute ethylene oxide units andR represents a monovalent hydrocarbon group having from 3 to 18 carbon atoms containing at least one sulphonate group --SO.sub.3.sup..crclbar. andto a process for their production.