Summary: The Vaccines for Children program was authorized by Congress in 1993 in order to increase immunization rates through free vaccinations. Plans by the Centers for Disease Control (CDC) to implement the program by October 1, as required by law, appear to be lagging behind schedule. With little margin for error, the program may not be up and running on time. GAO examined CDC's implementation plans and concluded that the time line is very ambitious. Several tasks integral to full implementation of the program are experiencing delays, including awarding contracts to vaccine manufacturers, developing plans for provider enrollment, and designing a vaccine distribution service that ensures the vaccine will not lose potency during shipment. Other components of the plan may need revision; for example, a proposed administration fee schedule may impose a financial burden on some program recipients, a consequence inconsistent with the program's stated goal of removing cost as a barrier to immunization. GAO also expressed concern that CDC has not yet developed plans for evaluating the program; without evaluation steps, it will be difficult to measure the impact of the program on immunization rates.