The IRS reports only 4 out of 5 people who qualify for the Earned Income Tax Credit actually claims it.
Grandparents and other relatives care for millions of children, but are often not aware that they could claim the children under their care for the EITC. A grandparent who is working and has a grandchild who is a qualifying grandchild living with him or her may qualify for the EITC, even if the grandparent is 65 years of age or older. Generally, to be a qualified grandchild for EITC purposes, the grandchild must meet the dependency requirements.
To be eliigble for the credit your grandchild must have been 18 years of age or younger at the end of the year, or a full time student and under the age of 24.
If you have a grandchild who is permanently or totally disabled there is an exception to the age requirement.
The grandchild must live for at least 6 months with you or your spouse, if you are using the status of Married Filing Jointly. If you are in the military and on extended duty outside of the United States special rules may apply.
The grandchild must have not filed a joint return, unless the grandchild or the spouse of the grandchild filed the return only to claim a refund.