I was on J1 visa for two years and worked as researcher

1) I entered in US on 15Nov 2006
2) I left US on 13th Nov 2008

I took benefit of tax treaty for two years and filed as non-resident and didn't paid fedral taxes for 2006, 2007 and also claimed back state taxes but paid medicare and SSN

For 2008, CINTAX is determining that I am a resident alien for this year. My question is

1) What forms shd I file for fedral taxes?
2) can I cliam back my ssn and medicare taxes? If yes, which forms to file?
3) Because I left US within two years. Can I still file as non-resident?

1) It would be helpful if you told us which country you come from, because the tax treaty dictates whether the exemption is for two calendar years or two years from date of arrival.

2) You ARE liable for the FICA (Social Securtiy and Medicare) taxes.

3) Probably; depends on the treaty.

Thanks..

Its India-US treaty as mentioned in subject line.

The Indian treaty allows for 24 consecutive months, so you should have been exempt from income taxes for the entire duration of your J-1 tour.

And, yes, you can file as a non-resident alien in 2008.