Di Matteo won the Champions League and FA Cup as caretaker manager last season and was given a two-year deal in June, however, after an impressive start to the season, the London-based club has won two of their last eight games.
"The team's recent performances and results have not been good enough and the owner and the board felt that a change was necessary now to keep the club moving in the right direction as we head into a vitally important part of the season," the BBC quoted a club statement, as saying.
"The club faces a difficult task ahead in qualifying for the knockout stages of the UEFA Champions League as well as maintaining a strong challenge for the top of the Premier League while competing in three other cup competitions. Our aim is to remain as competitive as possible and challenge strongly on all fronts," the statement added.
"The club will be making an announcement shortly regarding a new first-team manager," the statement said.
Owner Roman Abramovich has made contact with former Liverpool manager Rafael Benitez to gauge his interest in taking charge at Chelsea on a short-term basis.
Chelsea could become the first-ever Champions League holders to exit at the group stage the season after.
Former West Brom manager and Chelsea player Di Matteo, who had been working as assistant manager at Stamford Bridge, replaced Andre Villas-Boas in March. (ANI )