The Card Security Code (CSC) is part of a credit card authentication process established by credit card companies in their ongoing efforts to reduce fraud. For Visa, MasterCard, and Discover the 3-digit CSC# is located on the back of your card to the right of your card number. For American Express, the 4-digit code is located on the front of your card above the card number (see samples below).


Visa/MasterCard/Discover


American Express