My status was changed from F1 to H1 b since October 2013. I heard that I need to complete 180 days in a new status. As from 1st October till 31st December 2013 I have not completed 180 days, when I am filling for my tax returns, I will get back 100% of Social Security and Medicare tax return. Is this true? Please Advise.

Assuming you were on F-1 status prior to 1 October 2013, you will file as a non-resident and file Forms 1040NR-EZ and 8843 ONE LAST TIME, UNLESS you are married.

If you are married, let me know, because then you have another filing option available to you.

As for the FICA (Social Security and Medicare) taxes, you were exempt from these taxes UNTIL you converted to H-1B visa status. On the effective date of the H-1B, you became liable for FICA taxes.

Hence, you must go to your employer and ask for a refund of FICA taxes withheld prior to 1 October 2013. If they refuse (which IS likely), ask for a refusal letter on company letterhead stating how much of the Social Security and Medicare taxes you should get back. This refusal letter helps tremendously when you submit Forms 843 and 8316 to the IRS to get your FICA taxes back.

If you need professional help, email me at the email address in my profile.