The present invention relates to aqueous coating compositions containing A) at least one polyisocyanate which contains an average of at least two NCO groups per molecule and in which at least 85% of the NCO groups are blocked with a blocking agent selected from ε-caprolactam and/or a hydroxycarboxylic acid, and B) at least one hydrophilic polyester polyol containing an average of at least two reactive hydroxyl groups per molecule, or a mixture of hydrophilic and non-hydrophilic polyester polyols, wherein component B) has an acid number of ≧15 mg KOH/g, a hydroxyl number of 20 to 300 mg KOH/g and a weight average molecular weight, Mw, of >1500 g/mol, wherein the equivalent ratio between the blocked isocyanate groups of component A) and the isocyanate-reactive groups of component B) is 0.5 to 5.0:1. The present invention also relates to a process for preparing these aqueous coating compositions, to coatings obtained from these aqueous coating compositions, particularly coatings for packaging and for the interior of cans.