There are various ways to dispute the assertion by the IRS that you owe additional payroll taxes. Has the tax actually been assessed or have you simply been notified that you might owe this?  Also, if it has been assessed how long ago was the notice sent to you? You certainly might be able to appeal this notice of additional tax.  Generally you can appeal IRS decisions if you do so within 30 or 60 days.  Different types of adverse decisions have different appeal periods.  Was the assessment the result of an audit?  If not, perhaps we might ask for an audit to prove your position.  Have you filed all of your Form 941 quarterly returns?  This is a very important requirement. If not, you must file them as soon as possible, and the tax might be lower than the IRS calculated.  As you can see, the action you take depends on what has already happened. Even if the appeal period has passed, there are still ways to help you, such as Audit Reconsideration.