I receive $900 a month for SSDI. My husband earns $90,000 a year, so I am used to paying tax on a portion of my SSDI benefits, but I have never had to pay tax on my children's benefits they receive on my record because the amount is small. Last year, my 11-yo began receiving SSDI from my ex-husband's record due to he no longer being able to work after a massive heart attack. She now receives $1100 a month. Will this now be taxable???? I am confused and panicking a little.....

#1;Correct; as MFJ, aslongas yoru MAGI, provisional income, exceeds $32K, then some portin of of your SSDI is subject to fed tax.

#2; When you receive a payment for a dependent in your care from the SSA, the administration technically makes those payments to the beneficiary, not you. Because of this, custodians never owe taxes on these payments, and it shouldn't be reported as income on your Form 1040. The dependent may owe taxes on his/her benefits, but as a general rule, any beneficiary whose only income is from Social Security benefits -- such as children without a job -- benefits aren't taxable, and she doesn't need to file a tax return.So it depends; If the dependent for whom you serve as custodian earns income, such as wages from a part-time job, her tax situation changes slightly. Dependents who earn more than $6.100 a year, as of 2013, must file a tax return -- and will probably wish to file to qualify for an income-tax refund even if they don't reach the minimum-income threshold -- although in most cases, teenage workers most likely to be in your custody won't earn enough to report Social Security benefits as income when calculating their annual income. If the dependent for whom you act as a custodian receives significant income, her benefits may become taxable. To determine if her benefits are taxable, add 50% of her annual benefit on her annual income. If it reorted on 1040 line 37 exceeds $25K ,some of the dependent's benefits may be taxable.