When you travel to Poland, it may be a relief to know that major credit cards are generally accepted in business establishments - including shops and restaurants. Some of these will display the universal sticker on the door to signify to customers which cards they accept. If you are unsure, simply ask any staff member if credit cards are acceptable payment. A simple question, "Maestro?" (the more recognized term for Mastercard in Europe) will help you to get across your inquiry in an understandable fashion.
Credit cards can also be used to withdraw money from ATMs in local funds. Be sure to call your bank before you travel and indicate your intention to leave the country so your account is not frozen for security purposes, and ask about any fees you may incur upon using your credit card in Poland.
You should always carry cash, but in a bind, even some taxis will accept credit cards in Poland.
