Okay this is a tricky one...
After a separation the US citizen now lives and works legally in the EU, the permeant resident still lives and works legally in the US. How does one file taxes from now on?

Thanks in advance fro any help, great forum.

If they are married, they either file Married Filing a Joint Return or Married Filing Separately.

Both citizens and residents file a 1040 and report worldwide income.

If they are married, they either file Married Filing a Joint Return or Married Filing Separately.

Both citizens and residents file a 1040 and report worldwide income.

That was very fast, thank you very much.
So it's as simple as that? Basically when both of us lived together in the US and EU we filed together, we were having some horror visions about it getting complicated. How official is the term "separated" in the eyes of the IRS?

It depends whether your separation is just being physically separated, or being legally separated in lieu of or in preparatuon for a divorce.

If you are physically separated, you are STILL married, so you must file Married Filing Jointly or Married Filing Separately.

If you are legally separated, and you have NOT lived with your spouse for the last six months of 2009, then you may be "considered unmarried" and can file as SINGLE.

It depends whether your separation is just being physically separated, or being legally separated in lieu of or in preparatuon for a divorce.

If you are physically separated, you are STILL married, so you must file Married Filing Jointly or Married Filing Separately.

If you are legally separated, and you have NOT lived with your spouse for the last six months of 2009, then you may be "considered unmarried" and can file as SINGLE.

Thanks those were the answers I was looking for!

Glad to help!