Cardiometabolic risk comprises a cluster of traditional and emerging factors that are good indicators of a patient's overall risk for type 2 diabetes and cardiovascular disease. The insulin resistance, a key feature common to obesity and type 2 diabetes, is associated with impaired vascular response and contributes to increased cardiovascular risk. Abnormal vascular insulin signalling induces endothelial dysfunction, the initial step of atherosclerotic process, characterized by attenuated nitric oxide-mediated vasodilatation and atherogenic response. Insulin resistance and endothelial dysfunction are two pathological conditions that can co-exist, even if their cause-effect relationship is not yet clarified. Multiple signaling pathways shared by insulin resistance and endothelial dysfunction include hyperinsulinemia, glucotoxicity, lipotoxicity, and inflammation. These mechanisms selectively impair PI3K-dependent insulin in vascular endothelium harming endothelial balance and strengthening the evidence of the close association between metabolic and cardiovascular disease. The present review analyzes the close relationship between endothelial dysfunction and insulin resistance and explores the common mechanisms, with clinical considerations and pharmacological strategies.