My mother is a GC holder and has a SSN. Can I claim her as a dependent in my tax return. Last year she was out of US for couple of months.

Thanks in advance.

If you provided more than half of her support and her worldwide income is less than $3650, you can claim her as Qualifying Relative. Your U.S. Tax Return: Requirements for claiming a dependent

Thanks for your response. I buy my mother medical insurance as she is not covered by my employer's plan. Is there any way I can claim full or part of that as dependent care?

Negative, not unless you can claim her as a dependent.