Federal Regulations (8 CFR Sec.274a.12-14) established three categories of persons who are eligible to work in the U.S. First, there are persons authorized to work incident to their status (e.g., lawful permanent residents, people who were granted temporary protected status, fiancées). Second, there are persons authorized to be employed, incident to their status, with specific employer (e.g., H-1B, O-1). Finally, there are persons who must apply for employment authorization (e.g., applicant for asylum, withholding or cancellation, persons with final order of removal released under order of suspension).

As mentioned in the second category above, many nonimmigrant foreign nationals' are granted authorization for employment with a specific employer incident to their status. The following is a list of these nonimmigrant work-authorized categories:

1. Working visas - H, L, E, O, P, and R. (Spouses of L and E visa holders are also eligible to work.)
2. Government visas - A, and G (international organization)
3. Information media - I
4. Crewmen - D (but not with domestic voyages or flights)
5. Exchange student - J (if program permits)
6. Fiancees - K and K2 dependents
7. Students - F1 (on campus only) F1's must apply for off campus employment or practical training.
8. Canadians and Mexicans - (TN) entering U.S. as professional workers pursuant to NAFTA [INA Sec. 214(e)]

Nonimmigrants who change employers must file new petitions.Unauthorized employment is deemed a "per se" failure to maintain status. However, certain changes of employment are allowed without having to wait for the USCIS approval.

The USCIS District Director is vested with the power to revoke work authorization pursuant to 8 CFR Sec. 274a.14(b) if:

1. Good cause exists;
2. Conditions that favored granting permission to work no longer exist; or
3. Information in the application was not true.

The majority of adjustment of status ("green card") applicants become eligible to apply for work authorization upon filing the adjustment of status application.