A Third Preference applicant must have an approved Immigrant Petition for Alien Worker, Form I-140, filed by the prospective employer. All such workers generally require labor certification approved by the Department of Labor. Skilled Workers, Professionals, and Unskilled Workers (Other Workers) receive 28.6 percent of the yearly worldwide limit of employment-based immigrant visas, plus any unused visas from the Employment First Preference and Second Preference categories.

There are three subgroups within this category:

1. Skilled workers are persons whose jobs require a minimum of 2 years training or work experience that are not temporary or seasonal.
2. Professionals are members of the professions whose jobs require at least a baccalaureate degree from a U.S. university or college or its foreign equivalent degree.
3. Unskilled workers (Other workers) are persons capable of filling positions that require less than two years training or experience that are not temporary or seasonal.