Abstract: Aqueous dispersion of silane-functional polyurethane resins having a number average molecular weight of 10000 to 500000 and a silicon content of 1 to 30 mmol per 100 g of resin solids obtainable by reacting(A) adducts containing NCO groups, which adducts are obtainable by reactinga) one or more compounds having at least one ionic or ionisable and/or hydrophilic nonionic group, and more than one isocyanate-reactive group withb) one or more organic diisocyanates,(B) with polyesters having an OH value of 150 to 300 mg of KOH/g and more than three OH groups per molecule, which are obtainable by reactingc) polyalcohols withd) polycarboxylic acids ande) monofatty acids(C) optionally with linear polyesters having an OH value of 40 to less than 150 mg of KOH/g, which contain no monofatty acids, and(D) with organic polyisocyanates, wherein at least a proportion of the polyisocyanates has at least one functional group R.sup.1 OSi.tbd. in whichR.sup.1 means C.sub.1 to C.sub.8 alkyl or --C(O)R.sup.2 and R.sup.2 means C.