Labor Certification is a determination by the U.S. Department of Labor that there are not sufficient available and qualified U.S. workers for the position and that employing the foreign national will not adversely affect the wages and working conditions of U.S. workers who are similarly employed. Labor certification is the responsibility of the employer. All third preference immigrants must go through labor certification. Second preference immigrants must also go through labor certification, unless it can be shown that it is in the national interest to waive this requirement. First preference immigrants do not require labor certification.