Ronaldo is the second 'Galactico' in a week to commit to the Madrid giant, with Gareth Bale signing a new contract for a reported wage of over $750,000 per week.
Bale repaid that faith by scoring twice in the home win over Leganes in the Santiago Bernabeu stadium, his goals coming in a seven-minute spell in the first half.
Ronaldo, who has scored more than 350 goals for Real, drew blank and by his own standards is having a lean spell in La Liga, but he remains the club's most influential and likely highest paid player.
No details of his deal were given, merely a statement on the club's website to announce an "official event" in the presidential box of Florentino Perez Monday.
The new contract will tie Ronaldo to Real until he is 36.
He has previously helped his club to two Champions League crowns, one La Liga title and two Copa del Reys as well as the Supercopa, the UEFA Super Cup and FIFA Club World Cup since signing from Manchester United in 2009.
Manager Zinedine Zidane had been asked about Ronaldo's new contract after the win over Leganes which means his charges will top La Liga going into the international break.
"I'm happy because he is a player who has to finish his career in Madrid. It is unique," Zidane said in comments reported by Marca.
"His dream is to finish here and why I'm glad he has renewed and will end it his white shirt as I did."
Bale, who took the tag of world's most expensive player off Ronaldo when he signed in 2013, followed his fine strike in the 3-3 Champions League draw against Legia Warsaw in midweek with another impressive display.
Alvaro Morata rounded off the scoring to leave Real two points clear of arch-rival Barcelona, which beat Sevilla 2-1 in a match later Sunday. Vitolo put the home side ahead before Lionel Messi equalized for Barca.
Luis Suarez hit the winner for the reigning Spanish champion in the second half.
Zidane was content with his side's earlier performance, particularly the clean sheet, the first in 11 games
"We know the job we are doing and even 100 points doesn't guarantee that you win La Liga. It's getting harder and harder to win easy games, they don't exist," he added.
It also stretched Real's unbeaten run in all competitions to 28 games.
Further good news was the return as a second half substitute of influential midfielder Luka Modric after knee surgery.