Introduction: Two representative tests of endothelial function, flow-mediated dilation (FMD) and reactive hypermia index (RHI), often give contradictory results. Hypothesis: Simaltaneous evaluation of the interactions and discordances between two tests of endothelial function for different site might clarify the reasons for the contradictory results. Methods: A total of 966 patients were enrolled in this study. Simultaneous measurement of FMD and RHI by forearm cuff occlusion was repeated every 1.5 years during a 4.5-year observation period. Test results were divided by 4% of FMD and 1.67% of RHI, and the patients were classified into 4 groups. Lifestyle and blood laboratory values were also assessed at each examination. Data were analyzed on both a test-based and patient-based basis. Results: In a total of 1434 tests, there was little relationship between FMD and RHI. Blood glucose levels were negatively correlated with increased brachial artery blood flow velocity after cuff occlusion release (r = 0.095, p < 0.001). Increased blood flow velocity correlated with RHI (r = 0.144, p < 0.001), suggesting that there is an interrelationship between upstream and peripheral blood flow and that hyperglycemia worsens these flows. In addition, delayed time to peak diastole was associated with lower RHI (r=-0.111, p<0.001). Patient-based analysis showed that age, low-density lipoprotein cholesterol, and high-sensitivity CRP were highest in the low FMD/low RHI group, and fasting blood glucose was lowest in the high FMD/RHI group. Antihypertensive medication use, alcohol consumption, and smoking were highest in the low FMD/PAT group. Conclusion: The composite assessment by FMD and RHI is useful to indicate the pathological phenotype of endothelial dysfunction. The group with both low FMD and low RHI were found to be at higher risk. In addition, some FMD components were associated with RHI rather than FMD. A subgroup of patients with benign FMD, but with deteriorated RHI, had a longer time to reach maximal dilation. This possibility should be noted when assessing cardiovascular risk based solely on FMD.