I have custtody of my grandchildren and they receive social security benifit . do I report this as my income or their income

[myfatface]

I am retired and get a pension, but I have small grandchild who gets social security benifits from their mom/ my daughter's death and they are living with me. do I have to add their bennifit on my income taxes

[AlanT]

No, you do not have to add their benefits to your taxes and they do not have to file an income tax return. 

[DoninGA]

You do not enter a dependent's Social Security benefits on your tax return.  The SSA-1099 received for the dependent has their Social Security number in box 2 of the form.

If the dependent has no other income they do not file a tax return for the benefits received.