Low birth weight has consistently been associated with increased adult blood pressure. The relative importance of childhood growth is, however, less well established. This study examined sex-specific associations between childhood growth and adult blood pressure in 2120 subjects born from 1921 to 1935 in Reykjavik who were recruited into a longitudinal study in 1967-1991. Size at birth and growth at regular intervals between 8 and 13 years were collected from national archives. Hypertensive males did not differ from normotensive males at birth but were increasingly taller and of higher body mass index between 8 and 13 years. No differences in adult height were observed between hypertensive and normotensive males. For boys, growth-velocity (change in growth per year) for body mass index and height between 8 to 13 years was positively associated (P