The official and actual currency in the capital of Italy is the euro. This is good news for many European visitors who have euros too, you won't have to deal with exchanging money in Rome.
Fortunately, this is not a big problem for those of you who come to Rome and need to convert their money from other currencies. Let me answer some basic questions that new travelers can have when they travel from countries with a different currency.
The answer is very simple. You can hunt for euros in any ATM if you have your credit card. ATMs are all around the city, so there is no problem to withdraw money whenever you need it.
However, sometimes, especially if you are in the suburbs of Rome you may happen to be in a situation when you can't find an ATM and encounter people who don’t understand English. In this case I recommend you to write down the following functional phrase for “Excuse me, where is the ATM near here?”. It goes as follows “Scusi, dov’e il bancomat qui, per favore?”. Roman citizens are generally very friendly, so you will find your ATM in no time.
Well, quite often! it is very good to come to the capital with some cash already in your pocket. With cash you pay for your bus tickets, leave tips, pay for lavatory, buy things in small places such as tabaccherias (drugstores), food/newspaper kiosks, gelaterias and, of course, pay bills in the restaurants that take only cash, which sometimes can happen. Many ticket machines sell you tickets only in cash, too. Cash is quite normal for Romans and most preferable in payment. As you see, it is quite reasonable to prepare at least some euro cash before landing in Rome, because you will definitely need it.
There are also plenty of exchange offices for you in the city as well, it’s just a little bit less profitable for you, but if there is no other way at the moment - why not use it.
Another pro-cash argument is the terrible rates at the airport exchanges. Not only do they have bad conversion rates for you, they also charge fees for their services. So, bring euro with you!
Regarding the banks in Italy, you can’t exchange money in the bank unless you are a client of this particular bank, so there is no point trying to go there for this kind of purpose. In any way, you can easily withdraw cash from the thousands of ATMs around the city no matter if it’s your bank’s ATM or not.