The HIE-ISOLDE project aims at several important upgrades of the present ISOLDE radioactive beam facility at CERN. The main focus lies in increasing the energy of the radionuclide beams from 3 MeV/u up to 10 MeV/u through the construction of a superconducting post-accelerator. The upgrade substantially enhances research opportunities in most aspects of nuclear structure and nuclear astrophysics.