Introduction: We assessed the association of infant feeding with body composition and cardiometabolic health at 20 years in a setting where infant feeding is not associated with socioeconomic status. Materials and methods: Body size trajectory since birth, current body composition measured using whole-body dual-energy X-ray absorptiometry, and a broad range of cardiometabolic risk factors were compared cross-sectionally among young female university students who were ever breastfed (n = 158, 120 exclusively, and 38 mainly), mixed fed (n = 124), and formula fed (n = 15, 10 mainly, and 5 exclusively) Results: Compared with breastfed and mixed fed women, formula fed women had higher serum total and low-density lipoprotein (LDL) cholesterol although fat mass, fat distribution, fasting glucose, and insulin and high-density lipoprotein cholesterol did not differ. In addition, resting heart rates were higher in formula fed women compared with the other two groups of women although systolic and diastolic blood pressure did not differ. Further, formula fed women had higher adiponectin while serum leptin did not differ. There was no difference in birthweight, weight and height in childhood and adolescence, and glucose tolerance. On multivariate logistic regression analysis, formula feeding was associated with resting heart rates (odds ratio [OR]: 1.06, confidence interval [95% CI]; 1.01-1.12, p = 0.01) and adiponectin (OR: 1.3, 95% CI; 1.1-1.5, p < 0.001) independently of serum total and LDL cholesterol. Conclusions: Breastfeeding may be associated with favorable lipid profile and autonomic nervous function in young adults through mechanisms unrelated to adiposity, implicating potential long-term benefits of breastfeeding for cardiovascular health. Higher adiponectin in nonbreastfed women warrants further studies.