In addition to cardiovascular risk factors, Type 2 diabetes mellitus (T2DM) is associated with microstructural, structural, functional, and metabolic changes in the brain. Patients with T2DM tend to develop cognitive impairment and dementia. In this study, we report differences between groups of T2DM patients and age-matched healthy volunteers by comparing diffusion tensor and diffusion kurtosis metrics using the tract-based spatial statistics (TBSS) method. We found that all diffusivities are larger and the axonal water fraction is reduced in the T2DM group compared to the controls. This suggests presence of more water in the extra-axonal space.