This study sought to address underenrollment and late entry to early intervention by identifying factors associated with parental concern and services for developmental delays. The authors analyzed responses from 27,566 parents of children from birth to age 5 from the 2007 National Survey of Children's Health to quantify and to identify factors associated with developmental concerns and enrollment in public intervention or therapy. Developmental concerns were common among parents from all backgrounds, increasing as children approach preschool age and particularly among children with poor health and those with non-English home language. However, enrollment in intervention is low. Nearly 40% of parents reported one or more concerns, yet 5% of children were enrolled in public intervention or therapy. Multirace or Black race, non-English home language, low income, and private or no insurance were associated with lower odds of services enrollment. Primary health care provider and parent involvement were associated with higher likelihood of parent-reported concern and services.