(EN) The present invention relates to the delivery of biologically active molecules, such as peptides, nucleic acids and therapeutic agents, into the interior of cells by administering to the cells a complex comprising the molecule linked to an importation competent signal peptide. Such delivery can be utilized for purposes such as peptide therapy, gene transfer, and antisense therapy. -GOVT PAC ACKNOWLEDGEMENTS PAR This invention was made with partial government support under NIH Grant Nos. HL 30648 and HL 45994 awarded by the National Heart, Lung and Blood Institute. The United States government has certain rights in the invention.