Background: In certain regions of the brain, aphasia arises from a lack of understanding and regulating language following damage. About 35–40 percent of the people receiving hospitalization after stroke are identified with aphasia. The recently developed imaging methods for the analysis of the impact of brain lesion sites and sizes on aphasia are the Diffusion Tensor Imaging (DTI) and Fractional Anisotropy (FA). In order to reflect micro-structural integrity DTI may give data on the damage level of the white matter of the brain and subcortical neural structure. Objective: We examined the relationship between arcuate fasciculus (AF) and the prognosis of aphasia outcome after ischemic stroke utilizing DTI, and FA. Patients and Methods: In this study, which included 34 patients with post stroke aphasia, we investigated DTI and FA of arcuate fasciculus in predicting post-stroke aphasia outcome. Results: There was no significant association between the sex and Aphasia Handicap Scale (AHS) (P>0.05), while the age was significantly correlate with AHS (P<0.05). The vascular risk factors (hypertension, diabetes mellitus, smoking, dyslipidemia) were associated with poor aphasia outcome. In our study, we found that lesion size had significant effect on aphasia outcome. Also, the site of ischemic infarction site was important factor in determining aphasia outcome. In the Broca and Wernicke regions, AHS was greater than in the cortical injury, and in the insula and cortical injuries (1.92 ± 1.26) were the least common in patients. Conclusion: The site and the size of ischemic infarction significantly predicted s aphasia outcome, also the extent and mechanism of AF injury, which can be detected in DTI and FA, stood as a significant indicator on aphasia severity for patients with ischemic stroke.