Medicare patients in California will begin receiving their new Medicare cards in May. The new cards contain a Medicare Beneficiary Identification (MBI) number that replaces the current SSN-based number. There is a 21-month transition period during which physicians can use either number. The Centers for Medicare and Medicaid Services (CMS) has a web page to help physicians navigate the transition. Also, physicians can look up their Medicare patients’ MBI number through Noridian starting in June. Physicians should talk to their practice managers and health IT vendors to ensure their systems are ready to accept the MBI. For more information, go to