My niece got her H1b visa approved in early 2012 (Validity date from: 01/05/2012). Prior to that she was on a F1(OPT). Since she had valid EAD for OPT until end of Jan 2012, her employer decided to deduct income tax based on H1 status from Feb 2012 onwards. She did not change employers during the year.

Now for just the 4 days in 2012 does she have to file 1040NR? She did that last year as she was on F1 the whole year. Or is it OK if she files as a resident alient for whole year? HR block says she should be fine but there has been instances where HR block says something and I have found it to be incorrect.

We don't want this to be an issue later as she has applied for GC.

Thanks!

Technically, she needs to file a dual-status return, becayuse she did NOT spend every day in 2012 in H-1B status.

However, if she files as a resident for 2012, no one, to include the IRS, will notice or care.

Thanks @AtlantaTaxExpert, your name is all over the site, thanks for your help. But I think I forgot to include a crucial detail : She has been married all of 2011 and 2012 and her husband does not work / generate any income in US/abroad. He is neither a citizen nor a resident alien, he came to the country as my niece's dependent . Given that I think they can choose together to file either as non-resident or resident aliens. Correct?

I ran the numbers through both the models.
Filing as non-resident aliens they get only the treaty deduction of $5950
Filing 1040A (they also have a dependent child) they get the standard deduction for MFJ $11900 plus the exemption 3 x $3800 = $11,400

Then the recommendation should be to file 1040A along with the statement for choice of filing as specified by IRS, correct?

If she is married, then it is a no-brainer that she should file jointly as resident aliens with her spouse.

Duh me! Could you please clarify if there is no statement of choice needed? Thanks!

Yes, the residency choice statenent IS required, as well, as Forms W-7 to apply for ITINs for spouse abd child.