All U.S. citizens must have a valid passport to travel to Italy. Start the application process at least six months before you plan to go to Italy.
If you already have a U.S. passport, make sure that it still has three months' validity beyond the end of your planned visit to Italy.
Travelers coming directly from the United States do not need a visa to travel as a tourist in Italy for 90 days. Visas for other purposes--work, study or business--must be obtained from the Italian government.
U.S. tourists coming from another member of the Schengen Convention (mostly other European Union countries) don't need an Italian visa either, but they might be asked to prove their identity when entering the Schengen area. When going into the EU, get your passport stamped.
All non-residents must complete a dichiarazione di presenza (declaration of presence) after arriving in Italy. A passport stamped at an Italian border crossing counts as such a declaration; if you don't have one of those, your hotel can help you complete a declaration.
Customs officials at Italian points of entry may also ask to see proof that you have enough funds to stay in the country (often the possession of credit cards will be enough). They might ask to see your return tickets as well.
