Employment based immigrant visas are divided into five preference categories. Certain spouses and children may accompany or follow-to-join employment-based immigrants. Depending on the visa category, the employer may need to file a petition with the U.S. Citizenship and Immigration Service and a labor certification with the U.S. Department of Labor, describing the job and the prospective employee's unique qualifications for that position. In other categories, an immigrant may be able to file a petition for him/herself and no labor certification is necessary. Only a certain number of employment-based immigrant visas are approved each year. For information on numerical limits, priority dates and age cut-offs, please see the State Department’s Visa BulletinState Department’s Visa Bulletin.