Aim To investigate the effect of hypertension and insulin resistance on mononuclear cell binding to cultured endothelium. Methods Insulin sensitivity was estimated by modified insulin suppression test and endothelial adhesiveness for mononuclear cell was assessed by functional binding assay in 33 hypertensive patients and 32 normal controls. Results Mononuclear cell binding to endothelium increased in patients with hypertension compared to normal controls (35±9 vs 28±10,p<0.01). There was a positive relationship between mononuclear cell binding and mean arterial pressure (r=0.43,p<0.001). A positive relationship also existed between steady state plasma glucose (SSPG) concentration and mononuclear cell binding in both the hypertensive (r=0.61,p<0.001)and normotensive (r=0.71,p<0.001)groups. Multiple regression analysis demonstrated an independent relationship between mononuclear cell binding and both SSPG (p<0.001) and insulin (p<0.01). Conclusions Hypertension and insulin resistance enhance mononuclear cell adherence to cultured endothelium. It may be the linkage between atherosclerosis and both hypertension and insulin resistance.