Here is my situation:

Came into the u.s.: yr 2001 as F-1
Opt from may 2005 to September 2005
Change status to H-1B in Oct 1, 2005


I filed 1040 for the tax year 2005. Should I have filed 1040nr?

Here is my situation:

came into the u.s.: yr 2001 as F-1
opt from may 2005 to september 2005
change status to H-1B in Oct 1, 2005


I filed 1040 for the tax year 2005. Should I have filed 1040nr?


You should have filed 1040NR for 2005. File a 1040 for 2006. File an amended return for 2005 to correct it.

Agreed!