Objective: Is premorbid depression or post-injury depression related to differential volume loss in mild Traumatic Brain Injury (TBI)? Several studies suggest a neurotoxic effect of depression on left hemisphere hippocampal volume. Post-TBI depression also has been associated with reduced hippocampal volume. Method: This study was conducted on 22 individuals who had suffered a mild TBI and were seen at the one-year time point. This study acquired T1 MPRAGE MR images on a Siemens 3T scanner. Automatic brain parcellations for volumetric analysis were calculated using FreeSurfer. Subjects were assigned to groups based on the presence of a history of premorbid, post-injury or no depression. Learning was assessed using the California Verbal Learning Test, 2nd Edition. Analysis was conducted using MANCOVA to compare brain volumes between groups, controlling for age and total intracranial volume. Results: Results indicate that a history of depression prior to mild TBI is associated with lower volumes in the left parahippocampal gyrus but not in the left hippocampus, entorrhinal cortex, or anterior cingulate (p-value ≤ .01). Depression post-TBI was not related to volumetric differences and premorbid depression was not predictive of post-TBI depression. Moreover, premorbid depression and reduced volume in the left parahippocampal gyrus did not significantly reduce auditory-verbal learning performance. Conclusion: The results from this study indicate that premorbid depression is associated with lower left parahippocampal brain volume in mild TBI subjects. However, parahippocampal volume and premorbid depression was not associated poorer verbal learning after mild TBI.