Family-based Preference
Systems & Visa Number
Availability

4. Third Preference: Married sons and daughters of U.S. citizens
5. Fourth Preference: Brothers and sisters of U.S. citizens.

Visa numbers are issued based on the date of filing the preference petition with the USCIS. This date is known as the priority date. Petitions for immediate relatives are not subject to this preference system and visa numbers are immediately available upon filing the petition. The U.S. Department of State issues the "Visa Bulletin" each month with visa number availability based on current priority dates.

Certain immigrant visa petitions automatically convert to other
preference categories. These include:

1. First to third preference upon marriage of son or daughter of U.S. citizen
2. Immediate relative to third preference upon child of U.S. citizen marrying
3. Third preference to immediate relative upon the divorce of a child under 21
4. Third preference to first preference upon divorce of a son or daughter over 21 of U.S. citizen

5. Second preference to immediate relative upon naturalization of parent of minor, unmarried child

In some instances, a change in circumstances invalidates the petition and a new preference petition must be filed. For example, a petition for a second preference minor, unmarried child of a legal permanent resident becomes invalid upon the child reaching 21 and a new preference petition must be filed. However, this second preference petition is accorded the priority date of the initial preference petition.