The present invention relates to storage stable, aqueous polyurethane-polyacrylate hybrid dispersions, which are self crosslinkable at room temperature and contain A) 10 to 95 wt. %, of a polyurethane dispersion,B) 5 to 90 wt. %, of a polymer prepared in the presence of component A) from a mixture of vinyl monomers containing 0.5 to 20 wt. %, based on the total resin solids content of the hybrid dispersion, of a vinyl monomer containing acetoacetoxy groups andC) an at least difunctional primary or secondary amine, which is present in an equivalent ratio of amino groups to acetoacetoxy groups of 0.5:1 to 1.1:1,in which the wt. % of components A) and B) add up to 100, based on the total weight of components A) and B).The present invention also relates to one-component coating compositions containing these hybrid dispersions as binders and to substrates coated with these coating compositions.