Director Magaly Febles says contestants must be single, but it's been discovered that Carlina Duran wed in 2009.
Contest organizers have scheduled a Wednesday night news conference to give the crown to runner-up Dulcita Lieggi, who is 24.
The 25-year-old Duran was crowned Miss Dominican Republic on April 17 and was to represent her country at the Miss Universe contest. She has not commented publicly on her marital status.
Febles told the Dominican television news program Noticias SIN on Tuesday night that Duran acknowledged that she is married after the Dominican newspaper Diario Libre reported on its website that she was wed on June 6, 2009.