Mini in October 2012 announced its withdrawal from WRC.
Sordo competed for Citroen between 2005 and 2010 and has driven one of the French cars in 80 of his 98 world championship rallies.
HIRVONEN'S MATE
Citroen team
principal Yves Matton in a statement on Thursday, November 16, 2012: "We took our time in assessing the potential of the
drivers available to line up alongside Mikko Hirvonen next season.
Obviously, Dani was very high on our shortlist.
"Dani is very well liked in the team and it's a pleasure for everyone to see him return to the 'family'."
Matton said it was also important for Citroen to have a Latin driver for the southern European and Latin American markets.
Champions Citroen have won the drivers' title with Sebastien Loeb for the last nine years but the Frenchman will not race all 2013's rallies.
Finland's Hirvonen will become Citroen's main driver instead when the season starts in Monte Carlo on January 15, 2013.