The NPI Registry (National Provider Identifier) contains over 35 million registrants of health care providers who have registered to receive Medicare payments Finalized in 2008, the NPI numbering replaced the previous UPIN, OSCAR, PIN and NSC systems of identifying health care providers and suppliers NPI is a standard, unique identifier mandated by the The Health Insurance Portability and Accountability Act (HIPAA) All health care providers are eligible for NPIs