No, you can't get a tax break for "giving back" your salary. Once you accept it, it's yours. They'd be two separate transactions. You also cannot avoid taxes by refusing to cash your paycheck. The IRS operates under the assumption that money you get is income 'when it becomes available to you', whether or not you actually make use of it. In this case, the minute your paychecks were signed, they became income and only those actions deemed 'adjustments to gross income' or 'itemized deductions' are going to change that, and the adjustment can only be claimed in the year the action took place (e.g., you earn $50,000 in 2006. In 2007, you give $10,000 to charity. The deduction can only be taken in 2007, not 2006).