Cardiovascular risk factor variables were examined in a cohort of 440 infants from birth through 7 years of age. Anthropometric measures, BP, serum lipid and lipoprotein values, and dietary intake data were obtained according to detailed protocols. Various quality controls to ensure the collection of valid and reliable data were instituted. Participation remained high throughout the study with 80% of the children examined at 6 months and 60% at 7 years of age. Rates were slightly higher for black than for white children. Children born in the private hospital were more likely to continue in the study than children born in the charity hospital. Children of parents examined when the child was 2 years of age were more likely to be examined during the preschool phases, but parental examination was not related to child examination when the child was 7 years of age. As in studies of school-aged children, measurement errors were lowest for height, weight, and serum total cholesterol. Measurement errors for BP were highest at the younger ages, particularly for diastolic BP. Examination of a newborn cohort throughout time affords the opportunity to study early development of relationships and tracking of cardiovascular risk factors.