The U.S. Department of Health and Human Services (HHS), Centers for Medicare and Medicaid Services (CMS) has released proposed changes to the Medicare Outpatient Hospital Prospective Payment System (OPPS), including several proposed changes to Medicare Graduate Medical Education (GME) payments. Hospitals with existing GME programs, those that are contemplating new or expanded GME programs, and those considering closure of programs or sale or acquisition of a hospital should carefully review the proposed regulations to evaluate the effect of the proposed changes and consider submitting comments to CMS before August 31, 2010.