Hello ,

I am working full time on F1 visa and I am married.
My paychecks shows deduction of social security and medicare taxes where I am liable for exemption to these taxes begin on F1 visa.
I work for startup and my employer is unaware of these things. What should I do get it corrected. Do I need to file new w4 ? What could be mistake before ?

Download IRS Pub 519 from Internal Revenue Service and print off pages 49-60. Somewhere in that printing is the explanation that F-1 students are exempt from FICA (social security and Medicare) taxes.

Take that to your employer's HR or payroll and ask for a refund of the FICA taxes. The IRS REQUIRES you attempt to get the refund through the employer before submitting Form 8316 and 843.

If they refuse, let me know and I will tell you what the next step will be.

Thanks , I will do the needful.
I have question , what could have been wrong at first place ? from me or from employer ?
How to correct that in both the case .
Should I file a new w4 ?

The error is with your employer, but the W-4 has nothing to do with it, so a new one is NOT needed.

Thanks a lot....

Also, can you tell me what should be corrected from my employer side.I mean which form or document.
(I am the first F1 visa holder they have hired and hence don't know anything and I want to provide them the exact info so that this will be corrected as soon possible.)

Thanks a lot..

Ask them to refund the improperly-withheld FICA taxes and to stop withholding the FICA taxes from future pay checks.