Probably not. A real estate tax can be deducted only by the owner of the property upon which the tax is imposed. Therefore, if the deed to the property lies in your mother's name, you are not entitled to a deduction for the real estate taxes even if you are the one who actually paid them. Generally speaking, taxes are deductible in the year you pay them.

Sometimes real estate taxes are prepaid. If you are the property owner, you can generally deduct prepaid real estate taxes in the year of the prepayment if (1) you are a cash basis taxpayer and (2) you don't live in a jurisdiction where the taxing authority considers prepayment a "deposit." Jurisdictions vary regarding how they treat prepaid tax. Be aware that taxes placed in escrow generally aren't deductible.