Background: Endothelial dysfunction is regarded as an early marker for atherosclerosis & a precursor for future cardiovascular events. Objectives: Study was done to find out endothelial dysfunction (ED) in euglycemic & hyperglycemics. finding any endothelial dysfunction in high risk euglycemic & pre-diabetic individuals and compared degree of ED with different types of hyperglycemia, glycemic parameters & common cardio-vascular (CV) risk factors. MATERIAL & Methods: A cross-sectional, prospective study was done in subjects divided into two groups. First group included hyperglycemic individuals (80) Pre-diabetes( 20), Type1DM(20), Type2 DM (34), clinically labeled MODY(06) and second group included 40 euglycemic individuals. Body mass index, fasting lipid profile, FBS, PPBS, RBS, HbA1c were obtained. Endothelial dependent flow mediated dilatation was assessed with 7.5MHz high resolution ultrasound of brachial artery. A p-value of <0.05 was considered to be statistically significant. Results: Flow mediated dilatation was impaired with increase in age, BMI, lipid profile (p=0.04,0.02,0.02 respectively). FMD was seen inversely related to all glycemic parameters like FBS(r=.680,p=<0.001),PPBS(r=-.660,p=<0.001),RBS(r=.680,p=<0.001), HbA1c(r=-.820,p=<0.001).Flow mediated dilatation was impaired in Pre-diabetes, Type 1 DM,Type2 DM, Clinical MODY, but did not show significant difference between each other (9.03+0.73% vs 8.21+1.18% vs 6.95+2.14% vs 9.4+0.45%,p=0.20) but had significant difference when compared to euglycemics (14.01+3.06%,p=<0.001).FMD was impaired even in high-risk euglycemics(p=0.02) Conclusion: Results showed impaired endothelial function in hyperglycemics and endothelial dysfunction was seen even in Pre-diabetes and in high risk euglycemic individuals, thus showing endothelial damage in these early stages. Endothelial function declined with increase in the severity of glycemic parameters and common CV risk factors. Our study suggested FMD should be considered as a surrogate marker for future cardiovascular events.