Aims Emerging evidence suggests Type 2 diabetes (T2D) may adversely affect cerebral hemodynamics and oxygenation. This study aimed to explore the impact of uncomplicated T2D on cerebral hemodynamics and oxygenation during maximal exercise. Methods In a comparative clinical trial, 30 matched pairs of subjects with obesity, stratified by T2D status, were enrolled. Hemodynamic and oxygenation parameters were assessed during incremental maximal exercise. Additionally, physical activity levels, lipid profiles, and insulin resistance markers were evaluated. Results Participants with T2D exhibited significantly impaired cerebral blood volume (total hemoglobin) and oxygenation (oxygenated hemoglobin) compared to controls, especially at exercise intensities above 80 % of VO2peak. This impairment was independent of differences in arterial carbon dioxide partial pressure (PaCO2) levels between the groups at peak exercise (P textgreater 0.05, PaCO2 34.4 ± 3.2 vs 34.5 ± 1.3 mmHg). Moreover, individuals with T2D had a lower estimated glucose disposal rate (eGDR) compared to the control group (P = 0.02; 7.4 ± 2.4 vs 9.27 ± 0.97 mg/kg/min). Conclusions Our findings indicate that insulin resistance and hyperglycemia in T2D contribute to impaired cerebral hemodynamics and oxygenation, even before clinical signs of microangiopathy appear. These alterations could have significant implications for cognitive function and overall brain health in individuals with T2D.