OBJECTIVE. Preterm infants are at increased risk to develop insulin resistance and high blood pressure. The influence of growth during childhood is not well established. METHODS. We investigated childhood growth patterns in relation to blood pressure and insulin sensitivity, measured by the hyperinsulinemic euglycemic clamp, in young adults. We compared 29 subjects born preterm appropriate for gestational age, 28 subjects born preterm small for gestational age, and 30 subjects born at term with a normal birth weight. RESULTS. Insulin sensitivity expressed as Mi value (glucose disposal mg/kg/min (insulin levels pmol/l) × 100) was lower in infants in the POPS-AGA (18.2) and POPS-SGA (15.2) groups than in the CON group (24.7). Systolic and diastolic blood pressure (mm Hg) were higher in infants in the POPS-AGA (132/72) and POPS-SGA (127/71) groups than in the CON group (118/65). The preterm-born subjects, in lowest insulin sensitivity quartile had a higher height standard deviation score at ages 1, 2, and 5 years and a higher weight SD score at ages 2, 5, 10, 19, and 21 years than did those in the lowest insulin sensitivity quartile. The infants in the highest systolic blood pressure quartile had a higher height SD score at 3 months of age and at ages 2, 5, 10, 19, and 21 years and a higher weight SD score at ages 1, 2, 5, 10, 19, and 21 years than those in the lowest systolic blood pressure quartile. CONCLUSIONS. Young adults born preterm have lower insulin sensitivity and higher blood pressure than controls. Increments in height and weight during childhood are associated with lower insulin sensitivity and higher blood pressure in adulthood. Copyright © 2008 by the American Academy of Pediatrics.