Hi,
I am a citizen of india. I was working here in US three times during 2010. First time I was in L1 visa(jan- Mar) The second trip on B1 visa lasts for 53 days (I got daily allowances here for those 53 days).Salary was paid in India. Then again I came here back in novemeber and continuing my work. All together I stayed for 174 days. Do I need to pay full federal tax. I am married and in all three trips I didn't brought my family.
Thanks,
Regards,
Jai

Who paid you during L1 and since Nov 2010?

My employer in US (my employer is a US based company having branch in India)

My employer... (my employer is a US based company having branches in india)

Evidently, the employer must have deducted SS tax and Medicare tax. Your income is taxable in the U.S. You will file nonresident tax return.
You can also choose to file joint return as residents. For this you must wait to file your tax return for 2010 till you complete Substantial Presence Test in 2011. Your U.S. Tax Return: Substantial Presence Test (http://taxipay.blogspot.com/2008/04/substantial-presence-test.html)

You can also file as a non-resident (because you have NOT met the Substantial Presence Test) and pay NO taxes on the income earned while under the B-1 visa, since that income was India-sourced. The daily allowances under the B-1 visa would NOT be taxable.