Is there a maximum limit for deductions on payroll?

It used to be that if you claimed more than 10 your employer had to forward copies of your W4 in to the IRS for their review. This ruling was changed recently. So the answer is that you can claim as many dependents on your W4 as you want, BUT the IRS has the right to question the number you claim. They can do this if you end up with no taxes being withheld or if they believe you have supplied innaccurate information on the W4 form. You may have to write to them and justify why you are claiming 16 dependents for example. If the IRS doesn't like your answer they can direct your company to take withholding taxes out for 9 dependents (or whatever they think is right). The employer has a limited amount of time (45 days I believe) to comply with this directive.