Medel has played more than 50 times for Chile, including at the 2010 World Cup in South Africa, and spent two seasons with Sevilla.
Cardiff: Newly promoted Cardiff have signed Chile midfielder Gary Medel from Sevilla for a club-record fee to strengthen their squad ahead of the club's first season in the Premier League.
Cardiff said Medel has signed a four-year deal, subject to a work permit, having passed a medical exam on Saturday.
Cardiff manager Malky Mackay called Medel "a tenacious and intelligent international midfielder," adding that "his experience will be an invaluable asset to our squad."
Medel has played more than 50 times for Chile, including at the 2010 World Cup in South Africa, and spent two seasons with Sevilla in the Spanish league.
Cardiff did not disclose the transfer fee, but said it was a record for the club.
Medel will link up with his new team after international duty with Chile, which plays Denmark in a friendly on Wednesday.