Hi, I am in US on a J1 Visa. I come from Italy and I am eligible for the tax exemption treaty for 2 years. Can I open a roth or a IRA ? Thank you.

I assume that you mean that, for 24 consecutive months starting on the date of your arrival, your income is tax-exempt because you are under the J-1 visa that is granted to a teacher, scholar, researcher or visiting academic.

If so, you have NO requirement to file a tax return for at least one year and perhaps parts of two others, because you have NO taxable compensation. Note that you DO have to file Form 8843 and possibly a state tax return (some states honor the J-1 tax exemption; other states do not).

Since you have NO taxable conpensation, you CANNOT open and fund either a traditional IRA or a Roth IRA.