N,N-(di)alkylaminoalkyl(meth)acrylamide or N,N-(di)alkylaminoalkyl (meth)acrylate and/or a quaternary ammonium salt thereof are prepared with a low content of a compound of formula (IV) wherein R5 in each case is a linear, branched or cyclic alkyl radical, an aryl radical which may also be substituted by one or more alkyl groups, the linear, cyclic or branched alkyl radical may have a length of 1-12 carbon atoms and is, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, isooctyl, nonyl, decyl, undecyl, dodecyl.