While the national health care debate continues, states continue to design and improve their Medicaid programs working within the flexibility allowed under existing federal Medicaid law, using longstanding tools such as Section 1115 waivers to best meet their state’s unique needs. This primer is designed to make that job easier by answering the eight most common and consequential questions about Medicaid Section 1115 waivers. In this booklet, we review some of the most important recent and proposed changes. We conclude with information about where to find information about the changing status of waiver applications, and offer resources and tools that can help state policymakers understand and engage in the waiver process.