Online casinos that accept Mastercard are not difficult to find. Since Mastercard is an internationally used and recognized credit card company, most online casinos will accept it and other major credit cards. However, you might find that online casinos have different procedures for accepting Mastercard, so you should be prepared for the information that you might need.
Mastercard casinos will display the Mastercard symbol on their cashier page at a minimum, but online casinos that accept Mastercard might even display the symbol on the home page as well. Online casinos know that for many gamers, credit cards are the most convenient and trusted form of payment when dealing with online transactions. This is particularly true for American customers, because many of the other payment types available on online casinos are unknown to Americans. For example, although I have never seen PayPal accepted on an online casino, there are always foreign owned and operated payment services that are similar. However, unless they have set up an account with one of these other merchants specifically for making purchases with overseas companies, few Americans will have heard of, let alone use these payment options. But most Americans will have at least one Mastercard.
Online casinos that accept Mastercard will attempt to prevent any kind of customer complaints or issues by requiring some information when you attempt to use your credit card that will prove that you are the authorized user of the card. At the very least, you will be required to enter the correct billing address and zip code during the authorization process. You may be asked to enter the three-digit 'security code' located in the signature panel on the back of the card. Some Mastercard casinos take it a step further; they require you to fax or mail to them a signed authorization form for each card that you want to use on their site.
Mastercard casinos might not always be able to accept payment from your Mastercard. There are two main reasons for this. If you have a Mastercard with a company that is particularly vigilant about unusual charges on your credit card, the company may reject the charge because they are concerned it could be fraudulent. You'll need to contact your credit card company to give permission for the transaction if this occurs. However, some credit card companies will not accept transactions from online casinos as part of their policies. It will depend entirely on the bank or merchant that issued you the card. If you encounter this situation, you will need to either use a different card or register with one of the foreign 'PayPal' type companies in order to play.
When you use your Mastercard to add to your account balance, be sure that you know what name will actually appear on your credit card bill. Chances are it will not be the name of the casino itself, but rather the name of the company that owns and operates the casino. You will probably see a transaction fee in addition to the amount you charged because you are completing a transaction with an international company and most credit card merchants charge a fee for doing so. Check with your credit card company about the rates ahead of time if you are concerned.