National currency of Ukraine is the Hryvna (Gryvna), UAH. One Hryvna is divided into 100 Kopecks. Operations in other currencies are forbidden with only a few exceptions. Some shops and hotels do not accept any foreign currency any more.
Importing foreign currency is limited and beginning with a definite amount it should be declared or registered in the National Bank of Ukraine. Usual expenses for the travel are usually lower than the amount necessary to declare. More details available on the web-site of the Ukrainian Embassy (List of embassies of Ukraine http://www.mfa.gov.ua/mfa/en/305.htm) or custom service (http://www.customs.gov.ua).
Exchange bureaus: Euro and US dollars could be exchanged almost everywhere, other currency can be exchanged only in large cities in a few exchange bureaus. It is not recommended to exchange currency anywhere else, but exchange bureaus, due to the high risk of fraud. Moreover, it is illegal.
Cash dispensers/credit cards: Besides, a sufficient number of ATM (automated teller machines) is available for you to get cash via maestro or credit cards. Visa and Mastercard are widely accepted, others cards are less common. In Kyiv and other centres of Ukraine it is possible to pay via credit cards in restaurants and hotels.
But it is hardly possible even in the oblast centres and not possible at all in small towns. If there is such an option, it takes often a long time. Quite often, especially at restaurants, the cards might be misused, that is why it is strongly advised to keep an eye on your credit cards.
Traveller’s Cheque: not always accepted and you depend on bank business hours.