ASN.1 first appeared within the X.400 standards of CCITT (International Telegraph and Telephone Consultative Committee, now called ITU-T, International Telecommunication Union - Telecommunication Standardization Sector) recommendations (red book), as at this time only the Message Handling System (MHS) protocols made use of that technique. X.409 document defines both the notation and the encoding rules attached to the notation.

At this time, the ISO (International Organization for Standardization) documents were still Draft International Standards, but they described the Notation and the Encoding Rules separately.

In 1987, ISO documents became standards, and were published. CCITT and ISO working groups are jointly held. This is why in the blue book from CCITT, the documents also appeared as recommendations X.208 (equivalent to ISO 8824) and X.209 (equivalent to ISO 8825). Although the form of the documents might be different, the technical contents of both sets of standards are the same. This version of the ASN.1 standards is commonly called ASN.1:1990.

ASN.1:1990 is planned for withdrawal as it has been superseded by ITU-T X.680-X.683 (1997).