Objective To determine whether patients with coarctation of the aorta (COA) were more likely to develop obesity compared with the general population or others with isolated forms of congenital heart disease. Study design We conducted a cross-sectional study of 160 patients who underwent COA repair at our institution between 1974 and 2009. Body mass index (BMI) measurements were obtained from the most recent clinic visit and at 5, 10, 15, and 20 years of age from retrospective chart review. BMI values were compared against established normal data to obtain age-sex matched z-scores. We also compared the rates of developing obesity over time in adults with COA vs 96 adults with other isolated forms of congenital heart disease, including aortic valve stenosis, pulmonary valve stenosis, or atrial septal defect. Results After age 5 years, patients with COA had significantly greater BMI z-scores compared with age-sex matched normal data (P < .001). The proportion of obesity in patients with COA significantly increased over time (P < .001). Adults with repaired COA developed obesity at a greater rate than those with either aortic valve stenosis (P = .004) or with pulmonary valve stenosis or atrial septal defect (P < .001). Conclusions There is a greater incidence of obesity that progressively increases with age in patients with repaired COA. Adults with repaired COA developed obesity at a greater rate than those with other isolated forms of congenital heart disease. Further prospective trials are needed to confirm our observations and to elucidate the potential mechanism relating COA to obesity.