Visa or Mastercard This number is printed on your MasterCard, Visa & Discover cards in the signature area of the back of the card. (it is the last 3 digits AFTER the credit card number in the signature area of the card). American Express You can find your four-digit card verification number on the front of your American Express credit card above the credit card number on either the right or the left side of your credit card. [ Close Window ]