Current transient measurements are carried out on ion‐implanted polymers to provide new information on the mechanism for the implantation‐induced conductivity. Using metal‐oxide‐semiconductor field‐effect transistor devices in which implanted polymer films form part of the metal‐oxide‐semiconductor structure, the dispersion parameter &agr; is measured as a function of ion fluence and temperature. The fluence dependent measurements provide evidence for trapping sites and support a trap‐controlled hopping mechanism for ion‐implanted polymers. The temperature‐dependence measurements favor conduction by hopping between traps in the defect band in the mobility gap rather than between traps in the mobility edges. New results are also presented on the dc conductivity of polymers implanted at low temperature (77 K), the same samples as were used for the current transient measurements.