Healthcare payment systems are complex and difficult to administer. Over the years, providers have developed a complex process, called revenue-cycle management, for administering their interactions with payers operating under various payment systems. The Patient Protection and Affordable Care Act of 2010 will have a significant impact on payment systems—as will other recent reform measures. This paper contains primers on revenue-cycle management, health insurance systems, medical claims, claim coding, electronic-data interchange (EDI), claims processing, and public and private reimbursement methods for hospitals and physicians. But its focus is on the impact recent healthcare reform initiatives have had and are likely to have on payment systems and providers’ legal rights and obligations.