Their contracts expire at the end of the month and all three players are now free agents, the club said on its website. Ballack and Belletti are both approaching their 34th birthdays, while Cole has been dogged by injuries in recent seasons.
Ballack, Germany's national team captain, was ruled out of the World Cup after injuring his right ankle in Chelsea's 1-0 win over Portsmouth in the FA Cup final.
He moved to Stamford Bridge four years ago after a glittering career with Bayern Munich.
Ballack, who will be 34 in September, won three German league and cup doubles with Bayern before taking up the Premier League challenge.
The midfielder, who led Germany to the final of Euro 2008, has been linked with a return to the Bundesliga.
His agent, Michael Becker, told German broadcaster RTL that the player, who is on holiday in the United States, was "completely surprised" by the news.
Becker said Ballack would have been willing to take a pay cut to stay at Chelsea and would have accepted a one-year deal with an option for a second.
Cole, who is with England at the World Cup in South Africa, has been at Chelsea for seven years since leaving West Ham. He struggled to force his way into the Chelsea lineup this season after returning in September from an eight-month layoff with a right knee injury.
The creative 28-year-old midfielder helped Chelsea win the Premier League in 2005 and 2006 under former coach Jose Mourinho, but his progress has since been hampered by injuries.
He spent much of the 2006-07 season on the sidelines and ruptured the right cruciate ligament in January 2009.
Cole scored the last of his 40 goals for Chelsea in April as the Blues beat Manchester United 2-1 at Old Trafford to virtually secure the league championship. Along with United, the Londoner has been linked with two of Chelsea's city rivals, Arsenal and Tottenham.
Though Arsenal finished third and has a strong track record of Champions League soccer, Spurs has now reached the competition's qualifiers for the first time and is coached by Harry Redknapp, Cole's former boss at West Ham.
Redknapp has declared his interest in Cole, telling British media on Tuesday: "He is a great player, his contract is up and he is on a free transfer. When he returns I would love to talk to him about coming to Spurs."
Belletti, an attacking right back who can also play in midfield, joined Chelsea in 2007 after five years in Spain with Barcelona and Villarreal. However, the Brazilian struggled to establish himself for Chelsea.
He converted in the penalty kicks shootout of the 2008 Champions League final in Moscow, but started only 13 games for Chelsea this season.