The present invention relates to a targeting system comprising, preferably as distinct components, (a) a transposon which is devoid of a polynucleotide encoding a functional transposase comprising a polynucleotide of interest; and (b) a fusion protein comprising (ba) a transposase or a fragment or derivative thereof having transposase function; and (bb) a DNA targeting domain; or (bc) a (poly)peptide binding domain that binds to a cellular or engineered (poly)peptide comprising a DNA targeting domain; or (bd) a (poly)peptide comprising the DNA targeting domain of (bb) or the (poly)peptide binding domain of (bc), wherein the transposase or a fragment or derivative thereof having transposase function of (a) is joined by a linker to the domain of (bb) or to the domain of (bc) or to the (poly)peptide of (bd); or (c) a polynucleotide encoding the fusion protein of (b).