Peptide nucleic acids (PNA) are highly potential to be applied in antisense and anti-gene strategie. However, limited cellular uptake hinders applications of PNA in this purpose. Cell-penetrating peptides (CPP), short peptides that have the ability to translocate into cell membranes with cargo molecules, are able to translocate conjugated PNA oligomers into cells. Various CPP-PNA conjugates have been synthesized and showed increased cellular uptake and biological effects in gene silencing.