If I co-sign on my daughters student loans and she claims it on her taxes, do I still have to list it on my taxes?

[Hal_Al]

No.  It can only be reported on one return. 

She can claim the student loan interest deduction on her return if she actually pays it and can no longer be claimed as your dependent. 

[MinhT1]

No.

If your daughter paid the loan and claims the interest deduction on her own tax return, you do not list it on your own tax return.

Your daughter cannot your dependent if she claimed the student loan interest deduction.

Please read this IRS document for more information.