The Administrative Simplification provisions of HIPAA mandated the adoption of a standard, unique health identifier for each health care provider. The NPI Final Rule, published on January 23, 2004, established the NPI as this standard. Covered entities under HIPAA are required by regulation to use NPIs to identify health care providers in HIPAA standard transactions. This booklet contains information previously available in NPI fact sheet and tip sheets and can be found at: http://www.cms.hhs.gov/MLNProducts/downloads/NPIBooklet.pdf.