On the back of your Discover Card, there is an area where you sign your name. If your card was printed before July 2003, you will see two sets of numbers including your 16-digit Account number (see Card A) OR the last four digits of your Account number (see Card B). If your card was printed after July 2003, you will see three sets of numbers (see Card C or Card D).
Cards Printed Before July 2003
Cards Printed After July 2003
These numbers are part of the state-of-the-art technology that we employ to enhance security and cardmember convenience. The cardmember ID number is used to verify transactions made when the Card is not present, such as Internet or catalog purchases.
It is also required when registering for the Account Center. The sequence number, which always begins with the letter "A," will be used for future product and security enhancements.