PURPOSE: As compared to aged-matched healthy controls (AMHC), type 2 diabetes patients (T2DM) have an impaired aerobic fitness, cardiac hemodynamics, cerebral oxygenation/perfusion (COP) during exercise and an impaired cognitive function. Relationship between fitness, cardiac/cerebral hemodynamics and cognition are poorly studied in T2DM patients. The aim of this work was to study relationship among VO2peak, maximal cardiac index (CImax), COP and cognitive function in patients with T2DM. METHOD: Nineteen T2DM patients (62±7 years) and 23 AMH subjects (62±11 years) were recruited in this study. All subjects underwent a medical examination, blood sample analysis and body composition measurement. Gas exchange (Oxycon Pro; Jaegger, Germany), CImax (impedance cardiography: PhysioFlow, France) and left frontal COP (NIRS: Oxymon Mk III, Netherlands) were measured during and after a maximal cardiopulmonary ergocycle test (CPET). For COP, oxyhemoglobin (ΔO2Hb), total hemoglobin (ΔtHb) and deoxyhemoglobin (ΔHHb) were assessed. Cognitive functions (CF) were evaluated at rest by a complete neuropsychological test battery (13 different items) assessing perceptual abilities and processing speed, short/long-term/working memory (LTVM) and executive functions (EF). ANOVA was used to test group’s differences and Pearson correlation to evaluate the relationship between VO2peak, CImax, COP and CF (statistical significance for p<0.05). RESULTS: VO2peak, CImax and EF (Stroop 3 and 4) and LTVM were significantly lower (p<0.05) in T2DM vs. AMHC. Left frontal COP (HHb, O2HB and tHb) was not different between groups. VO2peak was positively correlated with tHB (R=0.35, p<0.05). Composite scores for EF was negatively correlated with O2HB (R=-0.40, p<0.05) and tHB (R=-0.37, p<0.05). VO2peak was positively correlated with substitution (R=0.369, p<0.05), negatively with trail B (R=-0.337, p<0.05). CONCLUSION: Patients with T2DM had a reduced aerobic fitness, cardiac output, executive functions and LTVM. Moreover, COP and aerobic fitness were related with executive functions and processing speed. It would be interesting to know the effects of training on VO2peak, cardiac index, COP and cognitive functions in T2DM patients. Supported by EPIC and Montreal Heart Institute foundations and CNPq.