Several studies have shown that low birthweight is associated with a higher risk of stroke and coronary heart disease in later life. Increased atherogenesis may be one underlying mechanism, but few studies have examined this directly. We used duplex ultrasonography to assess the extra-cranial carotid arteries of 389 elderly men and women born and still living in Sheffield, UK, whose recorded birth measurements were available. Men and women who had weighed 6.5 lbs or less at birth had a higher risk of having carotid stenosis >30% than those who weighed over 7.5 lbs, but this trend was not statistically significant (OR 1.8, 95% CI 1.0-3.3). Women who had been lighter or who had a smaller head circumference at birth tended to have an increased intima-media thickness, but these relations ceased to be statistically significant after adjustment for gestational age and cardiovascular risk factors. In men, by contrast, an increased intima-media thickness was associated with having been heavier at birth (P=0.049) or having had a larger abdominal circumference at birth (P=0.040), after adjustment for gestational age and cardiovascular risk factors. These results provide little evidence that impaired fetal growth increases susceptibility to atherogenesis.