By
eHow Personal Finance Editor
Difficulty: Moderately Easy
Step1
Check all the child's vital records. Your grandchild must be a U.S. citizen. The tax forms call for a social security number, which is also proof of citizenship. You should also have a copy of the birth certificate, in case of an audit.
Step2
Live with your grandchild for at least six months and one day out of the previous year. There are exceptions for vacation, school, work, military service or hospitalization, for instance. These exceptions are designed for not only the child's absence, but the grandparent's absence also.
Step3
Meet the age requirement. Grandchildren up to and including age 17 qualify for the child tax credit. The day that the child turns 18, he no longer qualifies for the tax credit.
Step4
Adhere to the support requirements. You must provide over half of your grandchild's financial support for the year. If the child has his own means, he cannot provide more than half of his own support for the year.