We have observed the destruction of fundamental building blocks of DNA (nucleoside, base, and sugar) by hyperthermal (0.25–1.75  eV/amu) heavy ion impact. Nucleoside damage pathways include base or sugar loss, and complete disintegration of either moiety. Sugar damage dominates, and in DNA will yield a complex strand break. Our results suggest that (a) heavy particle damage to biological media may extend to ion track ends beyond the Bragg peak, and (b) the nascent damage by hyperthermal secondary heavy particles, formed along the primary ion tracks, may be equally complex.