In the present study, we aimed to compare lower extremity tissue oxygen saturations in DM patients and healthy individuals. The study involved 22 patients with diabetes mellitus and 20 healthy subjects. StO2 of all participants was measured with near-infrared spectroscopy on the dorsal side of the foot. First, stO2 values between groups were compared, and then the DM group was divided into subgroups for further analysis. Median (IQR: 75th percentile-25th percentile) StO2 levels were 83.6% (84.2-83.0) in the patient group, while this was 81.3% (82.4-80.4) in the control group. In the comparison between groups, the patient group had significantly higher StO2 levels (p <0.0001). In the subgroup analysis of the DM group, patients with neuropathy, nephropathy, or coronary artery disease have significantly higher StO2 levels than patients without these complications or diseases. Our result showed that StO2 values in DM patients were higher than in healthy subjects, and in the presence of some complications, this elevation was even more pronounced. We attribute this situation to the inability of the cells to sufficiently utilize the oxygen due to metabolic dysregulation, and thus the oxygen saturation in the veins returning from the tissue remains high. We may call this pathophysiological capillary shunting, which became more pronounced in the presence of DM complications.