If you have been in US with F1 visa and less than 5 years, you shouldnt be withheld social security and medicare taxes. Here is what you can do:

first, you must ask your employer for a refund. If you are unable to obtain a refund from your employer,

then, you must file Form 843 and Form 8316 to obtain a refund from the IRS for the Social Security and Medicare taxes withheld in error by your employer.

read the post from this link: http://www.huaren.us/dispbbs.asp?boardID=336&ID=170326&page=1. look at #23:

23. Do I have to pay the Social Security tax?

Social Security (FICA) tax withholding depends on whether you are a resident or nonresident for tax purposes. If you are a nonresident F-1 or J-1student or nonresident J-1 scholar, you do not have to pay FICA. It is also important to note that if you are a resident F-1 or J-1 student but are working on campus, you do not have to pay the FICA tax. However, if you work without authorization, FICA should be withheld from your paycheck.

read the post from this link: http://www.huaren.us/dispbbs.asp?boardID=336&ID=170326&page=1. look at #23:

23. Do I have to pay the Social Security tax?

Social Security (FICA) tax withholding depends on whether you are a resident or nonresident for tax purposes. If you are a nonresident F-1 or J-1student or nonresident J-1 scholar, you do not have to pay FICA. It is also important to note that if you are a resident F-1 or J-1 student but are working on campus, you do not have to pay the FICA tax. However, if you work without authorization, FICA should be withheld from your paycheck.

It is also important to note that if you are a resident F-1 or J-1 student but are working on campus, you do not have to pay the FICA tax.请问这个得处处是什么？准备打出来给系里看。