Do you have to pay income tax on social imcome of 23000 I'm 89 years old?

It depends on your filing status and on whether you had any other income besides your Social Security benefits. Also, in order to determine whether your benefits are taxable, you have to count certain non-taxable income such as interest from tax-free municipal bonds.

If you did not have any income whatsoever other than $23000 of benefits, they would not be taxable unless you lived with your spouse and filed separately (in which case they would be taxable).

Please fill out Worksheet A on page 2 of Publication 915 to see for sure:

http://www.irs.gov/pub/irs-pdf/p915.pdf