As the number of purchases over the Internet has increased and the method of payment is a credit or debit card, e-commerce merchants must be able to accept on-line payment using the card data. Cyber-criminals have found ways to capture the information on credit and debit cards and use this information to make purchases and remove money from bank accounts which costs merchants lost revenue and chargebacks fees and cost consumers and banks lost funds.. The process by which credit and debit card payments are processed beginning with the e-commerce merchant's web site to a card processor or service gateway to the credit or debit card company's network to the issuing bank's network with an accept or decline response being returned to the merchant's shopping cart system via the same networks is discussed. The issue of credit and debit card fraud in terms of how cyber-criminals function and the solutions used to deter these attempts by the cyber-criminals is covered. The security standards and a list of preventive measures that should be used by e-commerce merchants are discussed.