The energy spectra of heavy ions emitted from laser-produced plasmas were determined by the use of a technique relying on the implantation of plasma ions into a substrate located close to the plasma. Ion energy spectra were reconstructed from depth profiles of the implanted ions measured by the standard Rutherford back-scattering (RBS) technique employing 2 MeV alpha particles scattered at 170° laboratory angle. The energy spectra of Ag, Au, Sn, and Pb ions, implanted into aluminum or steel foils, are presented. A review of other techniques for ion energy spectrum measurement is presented and their limitations are discussed.