Ronaldo, through his personal branding agent Jorge Mendes - who also represents Mourinho in offering to public and private organizations the for-profit right to use his image in advertisements - has denied any wrongdoing.
It will now be up to a judge to decide whether the matter should proceed to court.
In a statement released on Tuesday, a prosecutor in Madrid said the 54-year-old had committed two counts of tax fraud in 2011 and 2012, saying that "corporate structures were used by the accused in order to hide revenues generated from his image rights".
Ronaldo joined Real Madrid from Manchester United in 2009 for a then-world record fee of 96 million euros and is their all-time top scorer with 404 goals in 394 games.
Real Madrid did not respond to requests for comment on the allegations against Mourihno or Ronaldo's hearing.
Real Madrid president Florentino Perez made his first remarks about Ronaldo's stunning revelation in an interview with Spain'sOnda Cero radio, indicating that he is not looking to offload his star.
"I have not spoken with him since [the Champions League final in] Cardiff".
"He is not a business - he forms part of this club's history".
Rio Ferdinand hopes Manchester United can complete a sensational deal to take Cristiano Ronaldo back to Old Trafford. "We don't want to disturb his concentration with the national team", said Perez.
Mourinho lifted a La Liga title and Copa Del Rey during his time at the Bernabeu, before leaving in less than amicable circumstances at the end of the 2012/13 season.
That would leave four weeks before he is due to appear in court, with the date falling in the middle of Madrid's US tour. He also won the Champions League twice with Porto (2004) and Inter Milan (2010).
In Spain, sentences of under two years are normally suspended.
Barcelona footballer Lionel Messi was given a 21-month sentence past year, which he is unlikely to serve, for having defrauded the national purse of 4.1 million euros of undeclared image rights earnings.
Perez has dismissed speculation that Ronaldo is trying to put pressure on Real so that they will bear some of the burden of an eventual fine for tax evasion as Barcelona did for Lionel Messi.
Neymar, his father, and Javier Mascherano have also had their troubles with tax over the last couple of years.