Previous studies suggest that the inverse association between birth weight and adult blood pressure amplifies with age. Rapid childhood growth has also been linked to hypertension. The objective of this study was to determine whether the association between childhood growth and adult blood pressure amplifies with age. The study comprised 574 women and 462 men from the Helsinki Birth Cohort Study who attended a clinical study in 2001–2004 and a follow-up in 2006–2008. Mean age at the clinic visits was 61.5 and 66.4 years, respectively. Blood pressure was measured at both occasions. Conditional growth models were used to assess relative weight gain and linear growth. We studied the associations between conditional growth and blood pressure as well as the presence of hypertension. Relative weight gain and linear growth between ages 2 and 11 years were inversely associated with systolic blood pressure at mean age 66.4 years, after adjustment for sex, blood pressure at mean age 61.5 years, as well as other covariates. A one s.d. increase in linear growth between 2 and 11 years was associated with an OR of 0.61 for hypertension at mean age 66.4 years. Contrary to previous studies, we have shown an inverse association between childhood growth and adult blood pressure. There were, however, no associations between childhood growth and systolic blood pressure at mean age 61.5 years indicating that the beneficial effects of a more rapid than expected childhood growth might become more apparent with increasing age.