We analyzed previously unavailable data to describe the national health status in 1981 of noninstitutionalized children who were low birth weight infants. They were compared with normal birth weight children. All data contained in the analysis were based on weighted national estimates. Low birth weight children in general were found to have more chronic conditions, more hospitalizations, more days in bed because of illness, more limitations of activity, poorer health status as perceived by parents, and more school days lost because of illness. However, numbers of physician visits were not different even for low birth weight children younger than 2 years, which is inconsistent with the higher proportions of multiple hospitalizations, chronic conditions, and other illness measures. The proportions of children in the younger age groups at risk for health problems associated with low birth weight should be increasing. The proportion of very low birth weight children in the younger age groups with higher excessive morbidity measures tends to support the possibility. The increased survival of high-risk infants raises concern about their future requirements for special medical and educational services, and about the resulting stress on their families. Normal birth weight children were found to make a major contribution to the prevalence of morbidity. It is not the children identified as at risk as a result of low birth weight that comprise most of those with illnesses. The physical, social, and psychological environment after birth probably has the largest impact on the health status of our children. The attributable risk of excessive morbidity associated with low birth weight and very low birth weight reinforces the concept that while the overall impact is not large, the consistent pattern of poorer health for children born with low birth weight, compared to those of normal birth weight, shown in this analysis, is striking. The pattern reinforces concerns with the many factors associated with low birth weight and their effects on the present and future health of the population.