Adverse health effects caused by lead exposure include intellectual and behavioral deficits in children and hypertension and kidney disease in adults. Exposure to lead is an important public health problem, particularly for young children. Eliminating blood lead levels (BLLs) >/=10 microg/dL in children is one of the national health objectives for 2010 (objective no. 8-11). Findings of National Health and Nutrition Examination Surveys (NHANES) from the period 1976-1980 to 1991-1994 reveal a steep decline (from 77.8% to 4.4%) in the percentage of children aged 1-5 years with BLLs >/=10 microg/dL. However, BLLs remain higher for certain populations, especially children in minority populations, children from low-income families, and children who live in older homes. This report updates estimates of BLLs in the U.S. population with the latest NHANES data, collected during 1999-2002. The findings indicated that BLLs continued to decrease in all age groups and racial/ethnic populations. During 1999-2002, the overall prevalence of elevated BLLs for the U.S. population aged >/=1 year was 0.7%. BLLs in non-Hispanic black children remained higher than in non-Hispanic white or Mexican-American children, although the proportion of BLLs >/=10 microg/dL in this population decreased (72%) since 1991-1994. Approximately 310,000 children aged 1-5 years remained at risk for exposure to harmful lead levels. Public health agencies should continue efforts to eliminate or control sources of lead, screen persons at highest risk for exposure, and provide timely medical and environmental interventions for those identified with elevated BLLs.