<prompt> Human: So my employer messed up and accidentally paid me my bonus as an expense reimbursement, meaning I received all of it and didnt pay any taxes on it. I know that I owe taxes on this, but dont know the best way to go about it.Should I write my employer a check for that amount as a refund, and have them issue it to me again correctly?Or can I take care of this somehow while filing taxes next year?  <response>: Tell them to withhold the taxes on it from your next paycheck.That is easier than writing them a check and getting paid back.Regardless the IRS wont care about you paying them back, etc. They will only care what the W-2 shows, assuming of course it is accurate.Worst case scenario, send 25 of it to the IRS as an estimated tax payment this quarter and you wont have a penalty from it. Your employer still needs to figure out the FICA. 