Developmental disabilities (DDs) are chronic conditions that initially manifest in persons aged < or =18 years and result in impairment of physical health, mental health, cognition, speech, language, or self-care. The majority of persons with DDs require long-term supportive care or services. In 2003, RTI International (Research Triangle Park, North Carolina) and CDC analyzed data from multiple surveys and reports to estimate the direct and indirect economic costs associated with four DDs in the United States. On the basis of that analysis, estimated lifetime costs in 2003 dollars are expected to total 51.2 billion dollars for persons born in 2000 with mental retardation, 11.5 billion dollars for persons with cerebral palsy, 2.1 billion dollars for persons with hearing loss, and 2.5 billion dollars for persons with vision impairment. These estimates underscore the need for effective primary and secondary prevention measures (e.g., newborn screening for hearing and metabolic disorders and smoking-cessation counseling for pregnant women) to reduce the costs associated with DDs.