We investigate temperature effects on exciton dissociation dynamics in conjugated polymer systems. Using a modified version of the tight-binding Su-Schrieffer-Heeger model, the dissociation is studied under the influence of impurity effects with a nonadiabatic evolution method. Our results show that temperature effects reduce the critical electric field for the exciton dissociation. In the small temperature regime, the exciton is not trapped by the impurity and it is observed to perform a random walk, a fact not observed in the absence of temperature. This letter might enlighten the description of electroluminescence yields and charge transport efficiency in organic based electronic devices. (C) 2013 Elsevier B.V. All rights reserved.