In 1980, a randomized trial was conducted among 476 Dutch newborn infants to study the effect of a low or normal sodium diet on blood pressure during the first 6 months of life. At the end of the trial, systolic blood pressure in the low sodium group (n = 231) was 2.1 mm Hg lower than in the control group (n = 245). To investigate whether contrasting levels of sodium intake in infancy are associated with blood pressure differences in adolescence, we measured blood pressure in 167 children from the original cohort (35%) after 15 years of follow-up. We assessed the differences in systolic and diastolic blood pressure levels between the diet groups using a multivariate regression model with adjustment for potential confounders. The adjusted systolic blood pressure at follow-up was 3.6 mm Hg lower (95% confidence interval, -6.6 to -0.5) and the diastolic pressure was 2.2 mm Hg lower (95% confidence interval, -4.5 to 0.2) in children who had been assigned to the low sodium group (n = 71) compared with the control group (n = 96). These findings suggest that sodium intake in infancy may be important in relation to blood pressure later in life.