The 33-year-old midfielder, who has 100 caps with Greece, was club captain at Panathinaikos but he left the club on October 3 after his contract was terminated by mutual agreement in the wake of the Greens's disappointing start to the season.
"PAOK announces that as an agreement has been reached with the player Kostas Katsouranis. The international ace will be wearing the club's black jersey from January 2013 and for the next 1.5 years," PAOK said in a statement on Tuesday.
PAOK are second in the 16-team Super League, eight points behind leaders Olympiacos Piraeus after 14 games.
Katsouranis, a former AEK Athens and Benfica player, won his first cap in 2003, winning the European championship in Portugal in 2004.