The currency of Martinique is the Eastern Caribbean Dollar, however, US Dollars (bills, not coins) are generally accepted everywhere, as are Traveler's Cheques.  Be aware that if you use US Dollars or Traveler's Cheques, you'll receive your change in EC Dollars, not US.  If you plan to do a lot of shopping, Traveler's Cheques in small denominations, or better yet, the new American Express Traveler's Cheque Card, is an ideal way to safely shop nearly anywhere in the world.

The main banks are:

• Barclays Bank
• Royal Bank of Canada
• Bank of Nova Scotia
• St. Kitts-Nevis-Anguilla National Bank
• Nevis Co-operative Bank
• and Bank of Nevis

Banks are open 8am-2pm, Monday to Thursday; 8am-4pm on Fridays. On Saturdays the Bank of Nova Scotia (Bird Rock Branch) is open 8.30am-noon, and the Bank of Nevis is open from 8.30am-12pm. 

Each bank provides 24 hour ATM services where you can get cash advances from your VISA or MasterCard.  You can also withdraw cash from (or check the balance of) the primary checking and savings accounts linked to your bankcard, via the PLUS/Electron or Cirrus/Maestro networks.  Funds given by ATM, PLUS, or Cirrus/Maestro machines will be in EC funds, not US Dollars.  Remember to not take out too much more than you can spend on your trip, otherwise you'll have to either visit a bank on Nevis to exchange back to US Dollars, or lose some on the exchange rate, which is generally not as good at US Airports or banks due to fees.  Presently on Nevis the exchange rate is fixed at USD$1.00 = EC$2.68.

Most Martinique hotels, restaurants, and businesses accept credit cards, but it's best to check ahead before relying on just credit cards alone, as some smaller establishments do not accept them.  Also be sure to check what your credit card company is using for an exchange rate. 

BONUS TIP:  If your ATM pin code is longer than 4 digits, you should change it before traveling overseas - many foreign ATM machines do not accept more than 4 digits.  Also, if your pin is an alpha one, try to memorize the digits, and overseas ATMs often only display digits - not letters.  

Additional Resources:

• Martinique Offshore Banking, Investing, and Incorporation
• Xe.com Personal Currency Assistant  (pop-up currency exchange calculator)
• OANDA.com Currency Cheat Sheet  (prints a wallet-sized currency conversion chart)
• American Express Travelers Cheque Card  (the safest way to pay when traveling!)
• Martinique Financial Services (all about banking & financial services on Martinique - site run by the Ministry of Finance - their FAQ page is especially informative.)