GAO has designated Medicare and Medicaid as high-risk programs because they are particularly vulnerable to fraud, waste, abuse, and improper payments (payments that should not have been made or were made in an incorrect amount). Medicare is considered high-risk in part because of its complexity and susceptibility to improper payments, and Medicaid because of concerns about the adequacy of its fiscal oversight to prevent inappropriate spending. In fiscal year 2010, the Centers for Medicare & Medicaid Services (CMS)--the agency that administers Medicare and Medicaid--estimated that these programs made a total of over $70 billion in improper payments. This statement focuses on how implementing prior GAO recommendations and recent laws, as well as other agency actions, could help CMS carry out five key strategies GAO identified in previous reports to help reduce fraud, waste, and abuse and improper payments in Medicare and Medicaid. It is based on 16 GAO products issued from April 2004 through June 2010 using a variety of methodologies, such as analyses of Medicare or Medicaid claims, review of relevant policies and procedures, and interviews with officials. In February 2011, GAO also received updated information from CMS on agency actions.