If the babysitter is providing the childcare in her own home she is NOT your household employee. She is a childcare provider for you. You need her Social Security number or her Tax ID so that you can enter the amount you pay for childcare on your tax return in order for you to get the childcare credit. The babysitter is responsible for reporting her income on her own tax return. The amount you pay her and the amount she claims on her own tax return must match--the IRS does cross match.
There is no special form you have to fill out. Do be clear from the start with the babysitter that you will be reporting the childcare expense on your tax return so that she knows she must keep good records of how much she is paid. Write checks to her so you have a paper record of your expenses.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
