Disability benefits are not the same as unemployment benefits. You receive disability benefits because you are not able to work; you receive unemployment benefits when work is not available.
Disability pay may or may not be taxable - it depends on how you came by them. The TurboTax article Is disability income taxable? answers the most common questions on whether this income is taxable. Workmen's compensation, the most common form of "disability pay", is not taxable.
The IRS and most states, however, treat unemployment benefits as taxable income. Why is my unemployment being taxed?
