On June 1, 2020, the Centers for Medicare and Medicaid Services (CMS) revised its Medicare Fee-for-Service (FFS) billing instructions related to the response to the COVID-19 Public Health Emergency (PHE).  The revised instructions clarify when physicians, providers, and suppliers who bill for services provided to Medicare beneficiaries during the PHE must use modifier CR (catastrophe/disaster related) and/or condition code DR (disaster related) when submitting claims to Medicare. The revised instructions also include a chart of blanket waivers and flexibilities that require the modifier or condition code. The guidance is provided in CMS MLN Matters Special Edition Article SE20011.