Are disability and retirement income taxable?

Some social security or tier-1 railroad retirement benefits are taxable if the taxpayer received additional income during the year, according to the IRS. For 2014 taxes, if all income plus half of the taxpayer's retirement benefits equals more than $25,000, it is possible that part of the benefits are taxable.

If a couple is married and filing jointly, this threshold is raised to total $32,000 for 2014 tax purposes, says the IRS. If the only income received during the year was the social security disability or retirement benefits, they are generally not taxable. However, all income is taxable unless specifically excluded by law.