The Americans with Disabilities Act of 1990 (as amended 2008) (P.L. 110-325) prohibits discrimination against "otherwise qualified individuals with a disability who can perform the essential functions of the job either with or without a reasonable accommodation". The term “disability” means a physical or mental impairment that "materially restricts" one or more major life activities or situations in which an individual has a record of an impairment or the individual is being regarded as having an impairment. Additionally, the amendment provides that the definition of disability shall be construed in favor of broad coverage of indivudals under the act.

The act specifies that major life activities include, but are not limited to (non-exhaustive list), caring for oneself, performing manual tasks, seeing, hearing, eating, sleeping, walking, standing, lifting, bending, speaking, breathing, learning, reading, concentrating, thinking, communicating, and working. Major life activities also include the operation of a major bodily function, including but not limited to, functions of the immune system, normal cell growth, digestive, bowel, bladder, neurological, brain, respiratory, circulatory, endocrine, and reproductive functions. An individual is “regarded as having such an impairment” if the individual establishes that he or she has been subjected to an action prohibited under the law because of an actual or perceived physical or mental impairment whether or not the impairment limits or is perceived to limit a major life activity.