UN/EDIFACT stands for the United Nations rules for the Electronic Data Interchange for Administration, Commerce and Transport. They are a set of international standards, directories and guidelines for the electronic interchange of structured data, and, in particular, relate to trade in goods and services between independent computerized information systems (UN/EDIFACT Rapporteur's Team, 1990). The UN/EDIFACT work on EDI standardization developed from the need for a common international standard for the electronic transmission of commercial data.

In 1971, SITPRO, the Simplification of Trade Procedures Board in Great Britain began work on common EDI standards for Europe. In 1974, the UK EDI syntax called Trade Data Interchange (TDI) was published and was first used by UK customs authorities. In 1975, the UN began to develop terms of reference for international EDI standardization. In 1979, the United National Guidelines for Trade Data Interchange (UN/GTDI) syntax, based on the TDI guidelines developed by SITPRO was published.

By this time, the ANSI X12 standards were in use in North America. The value of merging the two to develop an international EDI standard was recognized and work was initiated within the United Nations/Economic Commission for Europe (UN/ECE) to develop the international EDIFACT standards.

The International Organization for Standardization (ISO) Standard which addresses EDIFACT is ISO 9735: 1988 Electronic data interchange for administration, commerce and transport (EDIFACT) -- Application level syntax rules (Amended and reprinted 1990). This standard includes:

• ISO/DIS 9735-1: Application level syntax rules -- Part 1: Syntax rules common to all parts, together with syntax service directories for each of the parts
• ISO/DIS 9735-2: Application level syntax rules -- Part 2: Syntax rules specific to batch EDI
• ISO/DIS 9735-3: Application level syntax rules -- Part 3: Syntax rules specific to interactive EDI
• ISO/DIS 9735-5: Application level syntax rules -- Part 5: Security rules for batch EDI (authenticity, integrity and non-repudiation of origin)
• ISO/DIS 9735-6: Application level syntax rules -- Part 6: Secure authentication and acknowledgement message (message type - AUTACK)
• ISO/DIS 9735-8: Application level syntax rules -- Part 8: Associated data in EDI
• ISO/DIS 9735-9 Application level syntax rules -- Part 9: Security key and certificate management message (message type- KEYMAN)