The invention relates to a method for carrying out the targeted transfection of cells, to compositions, which can be used for such methods, and to corresponding medicaments for use in gene therapy. The invention particularly relates to a method for introducing nucleic acid into cells involving the following steps: (a) mixing a nucleic acid with a dendrimer, whereby a portion of the dendrimer molecules is biotinylated; mixing the prepared complex, which consists of a nucleic acid and a dendrimer, with a second complex, which consists of an avidin or a streptavidin and of a biotinylated target-specific binding molecule, and; (c) incubating the complex prepared in step (b) with cells. Dendrimers that are well-suited for the invention are, for example, partially solvolyzed polyamidoamine (PAMAM) dendrimers. Target-specific binding molecules are, in particular, cell type-specific markers also of the cell surface of the target cells.