To determine the anemia trends among low-income US children, hematologic measurements obtained from children aged 6 to 60 months who were enrolled in public health programs in six states that were consistently monitored by the Centers for Disease Control Pediatric Nutrition Surveillance System were studied. Overall, the prevalence of anemia has declined steadily from 7.8% in 1975 to 2.9% in 1985. The prevalence of anemia declined significantly among children seen at preenrollment screening visits, as well as those seen at follow-up visits, suggesting a generalized improvement in childhood iron nutritional status in the United States, as well as a positive impact of public health programs. To ensure that the declining trend of anemia was not a function of a change in the population of children enrolled in the surveillance system, Tennessee nutrition surveillance records were further analyzed; these records were linked with birth records to obtain detailed socioeconomic status (SES) information. Even though the SES composition remained stable from 1975 to 1984, the prevalence of anemia has declined significantly within each SES group. These findings indicate a true decline in the prevalence of anemia among low-income children that is likely the result of improvements in childhood iron nutrition.