There has been limited examination of the effect of brain pathology on subsequent function. The current study examined the relationships between regional variation in grey matter volume, age and cognitive impairment using a semi-automated image analysis tool. This study included 69 individuals with mild-to-severe TBI, 41 of whom also completed neuropsychological tests of attention, working memory, processing speed, memory and executive functions. A widespread reduction in grey matter volume was associated with increasing age. Regional volumes that were affected also related to the severity of injury, whereby the most severe TBI participants displayed the most significant pathology. Poorer retention of newly learned material was associated with reduced cortical volume in frontal, parietal, and occipital brain regions. In addition, poorer working memory and executive control performance was found for individuals with lower cortical volume in temporal, parietal, and occipital regions. These findings are largely in line with previous literature, which suggests that frontal, temporal, and parietal regions are integral for the encoding of memories into long-term storage, memory retrieval, and working memory. The present study suggests that automated image analysis methods may be used to explore the relationships between regional variation in grey matter volume and cognitive function following TBI.