Hello,
I arrived to the States this last week and will do a post-doc (research) here. I was told to fill a 8233 form in order not to pay taxes in the US (as I already pay them in Italy). The first question does anyone know what is the Tax treaty article for Italy in the US? The second question is where do I find the additional required Pub. 519 (teacher? ) form that has to be filled in. I will appreciate any help and information on this subject.

Do you have J1 visa as researcher?

Unless the tax treaty between Italy and the U.S. exempt you from federal income tax (which depends upon your visa), you must pay taxes in the U.S. on the income while in the U.S.

As you already pay tax in Italy, it not a reason on which IRS will allow you not to pay tax in the U.S. This rule is same throughout the world.

If a U.S. citizen earns in Italy, he/she must pay taxes in Italy unless it is exempted by tax treaty.

I do have a J-1 visa as a researcher.
I cannot find the form "Pub. 519 " to be filled together with the 8233 form.
If you have a link to this Pub.519 form that would be great. Thanks

Publication 519 is not a form. You will file Form 1040NR or 1040NR-EZ.
Go to Internal Revenue Service and click More Forms and Publications. Then click link under Download forms and publications by,

You can find the article in IRS Pub 901.

The article is Article 20, Italy-U.S. Tax Treaty.

Thank you very much for the information!!

Glad to help!