I know others have posted on the topic, but I confess to having been a bit skeptical about the assurances others have given before. To understand my skepticism, you must know that my family member who has Celiac is EXTREMELY sensitive to the smallest amount of cross contamination. We rarely eat out in the States for this reason. I stand corrected- believe it - Italian restaurants really do understand gluten-free.
We have been very pleased with the Italian understanding of safely preparing gluten-free meals. While mostly we try to stick to places who advertise a complete gluten-free menu, we have also had the occasion of making the request at a traditional restaurant. The staff has let us know what they could safely prepare.
A few recommendations: Il Ristorante Nettuno near Paestum
In Roma: Voglia di Pizza near Campo di Fiori
Mama Eat in Trastevere
And our favorite, Soffitta Renovatio near the Vatican
We only wish we could get this amazing gluten-free pizza in the States!