the exchange rate fluctuates daily, and the rate you get drawing pesos from an ATM is as good as you're going to get. Same is true anywhere for whatever local currency you're getting ... Europe, etc. But there is the additional fee for the ATM (charged by the D.R. bank who owns the ATM.... usually a couple of dollars.) Depending on your U.S. bank, and the type of account you have, you might also have to pay a fee to YOUR bank. (I don't.) So... don't withdraw small amounts, because that fee is the same for 100 pesos or 10,000 pesos. Leverage it and draw a lot at one time. Overall, we're talking small differences... not enough to get your panties in a knot over.