What is a security code?
A security code is included on all recent VISA, MasterCard, Discover, and American Express credit cards.

VISA, Mastercard, Discover Cards
Your security code is the 3-digit number on the back of your card. Usually it is above the space where your signature goes.

American Express Cards
Your security code is the 4-digit number printed on the front of your card. The number is printed above the card's number on the right or left.

Example security code locations:

visa / mc card amex card