Abstract MeV energy ion-implantation induced modifications in simple binary glass As 2Se 3 have been monitored by dc conductivity measurements. The study testifies that the process of ion-implantation at MeV energy is a novel technique in modifying the electronic properties of semiconductors. Ni ion seems to have more drastic changes than Ag and Ge ions. As small a dose of 75 MeV Ni ions as 5 × 10 13 ions/cm 2 is sufficient to produce remarkable changes in the conductivity of bombarded samples. The ion-induced defects appear to get diffused to a much deeper extent than the projected range.