The Affordable Care Act (ACA) requires that most Americans have health insurance by January 1, 2014. To help achieve this coverage goal, the ACA includes several provisions calling for major changes in state eligibility and enrollment processes currently used in public health insurance programs. To a large extent much of the responsibility for creating these eligibility and enrollment systems resides with the states. In this brief we draw on the experiences of five statesColorado, Kansas, Minnesota, New York and Oregonthat had begun modernizing their eligibility and enrollment systems and processes prior to the ACA. We describe the best practices that these states have employed with regard to these activities, and consider the implications of these practices for implementing the ACA.