The present invention relates to Cardiac Targeting Peptides or CTPs that are able to transduce cardiomyocytes specifically in culture and in vivo, and to methods for using such peptides and their derivatives to deliver peptides, proteins or nucleic acids specifically to the heart. It is based, at least in part, on the discovery that the peptide APWHLSSQYSRT (SEQ ID NO:1) functioned as a cardiac-specific protein targeting peptide and was successful in delivering a number of different cargoes to cardiac muscle cells in vitro and in vivo.