Irina Walker, the daughter of King Michael I, the last king of Romania was arrested along with her husband John last year.
The pair are charged with running an illegal gambling operation while staging cockfights at their Oregon ranch.
As part of a deal with the government, the two pleaded guilty Wednesday in return for animal fighting and conspiracy charges being dropped.
The Oregonian reports Walker quietly told a judge, "I provided food and beverage, your honor, and the location."
Prosecutors in the case claim the Walker’s made big profits by charging an entrance fee and selling alcohol.
They also hired a woman to “make tacos” and run a concession stand.
Sentencing will be in October.