The term "essential functions" means the fundamental job duties of the specific position in question; it does not include the marginal functions of that position. See EEOC's Interpretive Guidance on Title I of the Americans with Disabilities Act set out as Appendix to 29 CFR Part 1630. See regulatory text for the following applicable regulations.

• Title I of the Americans with Disabilities - 29 CFR 1630.2(n)
• Title II, Subtitle A, of the Americans with Disabilities - 29 CFR 1630.2(n)
• Section 188 of the Workforce Investment Act of 1998 sites EEOC regulations, guidance and appropriate case law to serve as guidance - 29 CFR 37.10(c)
• Section 503 of the Rehabilitation Act of 1973, as amended - 41 CFR 60-741.2(u)
• Section 504 of the Rehabilitation Act of 1973, as amended - 29 CFR 32.14 of the Department of Labor's (DOL) regulations. DOL's Section 504 regulations are for recipients of DOL financial assistance. If your business or organization receives financial assistance from another Federal agency, be sure to consult that agency's 504 regulations.
• The Vietnam Era Veterans' Readjustment Assistance Act of 1974, as amended - 41 CFR 60-300.2(s)