Visual field deficits due to optic radiation injury are a common complication of temporal lobectomy in epilepsy surgery. In this prospective study, diffusion tensor imaging (DTI) based fiber tracking was performed on 48 patients who had temporal lobectomy for pharmaco-resistant epilepsy. Pre- and intra-operative DTI based fiber tracking was used to visualize the optic radiation and to predict the post-operative visual field defects. The course of the optic radiation could be successfully reconstructed by DTI based fiber tracking. There was a significant correlation between the fiber tracking estimation and the outcome of visual field deficits after surgery. The Receiver Operating Characteristic (ROC) curve analysis confirmed the accuracy and validity of prediction of the post-operative visual field deficits comparing pre- and intra-operative fiber tracking results. Intra-operative visualization of the optic radiation may help in avoiding post-operative visual field deficits.