Deep-level transient spectroscopy was used to investigate the electrically active defects introduced in n-type Ge during heavy-ion implantation of 160keV ions. Various noble heavy-ions were used for implantation and the main defects introduced were found to be electron traps with energy levels at E C −0.09eV, E C −0.15eV and E C −0.30eV. Another defect with a level at E C −0.38eV, shown to be the E-center (V–Sb defect), is also present in a very low concentration. The main defects in heavy-ion implanted Ge are different from those introduced by MeV electron irradiation, where the main defect is the E-center. Since electron irradiation introduces mainly point defects, this indicates that heavy-ion implantation introduces defects of a more extended nature, such as vacancy and/or interstitial clusters and their combinations with impurities or foreign species in the Ge. We have also demonstrated that these defects are not species related.