The implementation of Part C of IDEA has continued to evolve as states have built and modified service delivery systems. The number of children served has increased dramatically with nearly 350,000 children and their families now receiving early intervention services. Meanwhile, challenges to the provision of quality services--such as securing adequate funding, staffing programs with qualified personnel, and monitoring for quality--persist. A new development for Part C is the systematic collection of data on child outcomes. The upcoming reauthorization of IDEA presents an opportunity to further refine this important federal program for children less than 3 years old and their families.