The Juventus forward, who was facing charges stemming from his days at Real Madrid, was in court for about 45 minutes and signed an agreement which will cost him nearly 19 million euro in fines.
Ronaldo arrived at court in a black van and was wearing a black sports coat and black trousers.
He walked up some stairs leading to the court house and even stopped to sign an autograph.
Ronaldo made the deal to plead guilty with Spain’s state prosecutor and tax authorities last year.
In Spain, a judge can suspend sentences for two years or less for first-time offenders.