In Illinois, the amount of child support paid is directly a result of how much money the payor is making. If you have a child support order in place and are no longer making as much money as you used to, you have to continue to pay the same amount - UNTIL a new child support order is entered by your judge. Don't wait and expect the court to adjust back to the time that you started making less. For example, let's say that the amount that you are taking home changed on January first. On Feburary 15th you file paperwork with the court asking that child support reflect your changed income. On April 1, the judge enters an order allowing you to pay less child support since you are earning less. Up until April 1, you still have to pay the amount based off of the old order (and your higher income), although some courts will give you credit for the overpayment after February 15th (the date you filed). This way, you are neither rewarded for waiting nor penalized by any court delays after you file. Bottom Line: the only way to change the amount of support you have to pay is to have a new court order entered.