If my child has Autism, is that considered "disabled"?

[Opus 17]

For income tax purposes, disabled means "unable to perform gainful work."  So it depends on the degree of autism.  Gainful work is work done for at least minimum wage.  Work in a sheltered workshop or rehab facility does not count, but if a person can work a minimum wage (or more) job with reasonable accommodations, they are not disabled for income tax purposes. 

Also, for children under age 13, checking the box does not change anything on the tax return because there are no specific tax benefits for disabled children.  At age 13 and older, being disabled makes the child eligible for the child care credit (if you have to pay for child care because they can't care for themselves), and over age 18, being disabled may allow you to claim an adult child as a dependent even though they have aged out of the normal dependent rules. 

[Cynthiad66]

Not necessarily.  We are unable to determine for you whether you are disabled for IRS purposes. The qualifications are listed in IRS Publication 524 Credit for the Elderly or the Disabled, page 4:

You have a permanent and total disability if you cannot engage in any substantial gainful activity because of your physical or mental condition. A physician must certify that the condition has lasted or can be expected to last continuously for 12 months or more, or that the condition can be expected to result in death.