Adults who were small at birth have been reported to have higher systolic blood pressure and risk of ischaemic heart disease in later life. Conversely, in 616 subjects of less than 34 weeks' gestation and 1850 g birth weight, systolic and diastolic blood pressures at 7.5 to 8 years of age decreased with decreasing weight for gestational age and were not related to birth weight. These data do not support the view that fetal growth retardation before 34 weeks programmes for increased blood pressure in later life.