In 1997, Congress authorized payments to nurse practitioners (NPs) for Medicare-provided services. NP services are now reimbursed at 85% of the physician fee schedule. As this source of reimbursement was realized, so was a new area of liability for NPs. Failure to follow billing rules can result in payment denial, repayment of fees already paid, mandated educational activities, fines, fraud prosecution, loss of Medicare-billing ability, and loss of employment. Appropriate billing entails adhering to guidelines for selecting procedure codes and proper medical documentation. This article identifies high-risk areas for NPs who bill Medicare and provides resources for accessing additional information.