Described is an adhesive composition in the form of an aqueous polymer dispersion comprising tackifiers, a compound crosslinking via keto or aldehyde groups and a pressure-sensitive adhesive polymer which is formed by emulsion polymerization from soft (meth)acrylic ester monomers, acid monomers, monomers having keto or aldehyde groups, styrene and optionally further monomers, wherein the polymerization may be carried out in the presence of chain transfer agents. The pressure-sensitive adhesive polymer has certain gel contents. The pressure-sensitive adhesive composition may be used to produce adhesive labels, adhesive tapes or adhesive films.