The Administrative Simplification provisions of the Health Insurance Portability and Accountability Act of 1996 (HIPAA) mandated the adoption of a standard unique identifier for health care providers. The National Plan and Provider Enumeration System (NPPES) collects identifying information on health care providers and assigns each a unique National Provider Identifier (NPI).

The NPI is a unique identification number for covered health care providers. Covered health care providers and all health plans and health care clearinghouses are required to use the NPIs to identify health care providers in the administrative and financial transactions adopted under HIPAA. Health care providers are categorized by the NPPES as two types: individuals, such as physicians; and organizations, such as hospitals.

The NPI is a 10-position, intelligence-free numeric identifier (10-digit number). This means that the numbers do not carry other information about healthcare providers, such as the state in which they live or their medical specialty.