Background & objectives: Abnormal endothelial function represents a preclinical marker of atherosclerosis. This study was conducted to evaluate associations between anthropometry, cardiometabolic risk factors, and early life factors and adult measures of endothelial function in a young urban Indian cohort free of clinical cardiovascular disease. Methods: Absolute changes in brachial artery diameter following cuff inflation and sublingual nitroglycerin (400 μg) were recorded to evaluate endothelium-dependent and -independent measures of endothelial function in 600 participants (362 men; 238 women) from the New Delhi Birth Cohort (2006- 2009). Data on anthropometry, cardiometabolic risk factors, medical history, socio-economic position, and lifestyle habits were collected. Height and weight were recorded at birth, two and 11 yr of age. Ageand sex-adjusted linear regression models were developed to evaluate these associations. Results: The mean age of participants was 36±1 yr. Twenty two per cent men and 29 per cent women were obese (BMI > 30 kg/m2). Mean systolic blood pressure (SBP) was 131±14 and 119±13 mmHg, and diabetes prevalence was 12 and 8 per cent for men and women, respectively. Brachial artery diameter was higher for men compared with women both before (3.48±0.37 and 2.95±0.35 cm) and after hyperaemia (3.87±0.37 vs. 3.37±0.35 cm). A similar difference was seen before and after nitroglycerin. Markers of increased adiposity, smoking, SBP, and metabolic syndrome, but not early life anthropometry, were inversely associated with endothelial function after adjustment for age and sex. Interpretation & conclusions: The analysis of the current prospective data from a young urban Indian cohort showed that cardiometabolic risk factors, but not early life anthropometry, were associated with worse endothelial function.