Owner Roman Abramovich took the shock measure following a 3-0 defeat to Juventus in the Champions League that leaves Chelsea's hopes of progressing to the knockout stages hanging in the balance.
Chelsea have won only two of their last eight games in all competitions to slip four points off the lead in the Premier League.
However, it is only six months since Di Matteo won the FA Cup and then inspired Chelsea to become the first London club in history to win the European Cup.
So was his dismissal justified? Here's what some of sport's leading figures are saying...
"I will be curious to see what they do in the next couple of days. I can't believe they have just sacked him out of the blue and then they'll be thinking about who is going to be the next one. I don't think so. I think they have already in mind who is going to be the next one. It could of course be (Jose) Mourinho, if it happens, I don't know because it is in the middle of the season." - Former Chelsea manager Ruud Gullit, who signed Di Matteo as a player in 1996.
"Wow, Chelsea have sacked their manager!! I'm a bit late I know but its a madness." - Manchester United defender Rio Ferdinand.
“People are saying that Fernando Torres being left out was the reason why Di Matteo lost his job but if you’re going to select centre-halves who are not doing their jobs then you are going to concede goals. The manager is paid to sort that out. He has to find a solution. When I saw Chelsea were playing without a centre-forward I thought that’s OK because they’re playing a style that will create a moment of magic from Oscar or Eden Hazard. You’re only going to get one moment of magic though and you’re going to need to keep a clean sheet. You can see that, when looking over the last few games, that was not going to be possible. Chelsea lost 3-0 but it could have easily been five or six. That is a big problem for a manager. It was inevitable this would happen if you’re going to lose games in that manner." - Former Chelsea striker Tony Cascarino.
"It just goes to show you how precarious we are as Premier League managers, and you can't take anything for granted. The shock that should be there for the fans and the media should sound something to the owner of that football club because I don't know if that's the ninth manager or whatever it is in so many short years. It's just not fair. As far as I am concerned, he has done absolutely nothing wrong. His philosophy was to perhaps change the look of the team, which he has tried to do - that doesn't happen overnight - and he's won two competitions in less than a year, so it's unbelievable. He should walk straight into another job - probably at someone else's misfortune, unfortunately." - Newcastle manager Alan Pardew.
"I know Roberto well and he is a good man so this is sad news. It's also quite incredible that he can be sacked so soon after winning the Champions League - and the FA Cup for good measure. It must be a record, and not a good one. It just shows that patience now seems a rare commodity at some clubs and that is a shame because the record of other successful clubs shows that stability can breed success. I am sure that it will not be long before another club recognises Roberto's qualities, and that he will soon be back in football." - PFA chief executive Gordon Taylor.
"I feel a little bit sorry for Robbie and no doubt Chelsea fans would say the same. But it's one of those jobs where they know what they are taking on when they take the job. The result last night and the situation they are in in the group as far as the Champions League goes meant the hierarchy decided to take action. " - Chelsea legend Kerry Dixon.
"Results and performances haven't been to the level of a club of this magnitude. Abramovich has always been good for Chelsea and will continue to be." - Former Chelsea defender Paul Elliott.
"Ridiculous decision from Chelsea... RDM wins the trophy they have been chasing for years and now gets the Boot...." - Former England cricket captain Michael Vaughan.
"Joke decision to sack DiMatteo. Wins Champs Lge & FA Cup. Currently 3rd in league. Need stability for sustained success. #nothappy" - Former England cricket captain and Chelsea fan Alec Stewart.
"Is everyone really that surprised by Chelsea-ovich getting rid of their latest play thing? It's football after all. If it's not broken, fix it." - QPR and Marseille midfielder Joey Barton.
"Can't believe Roberto di Matteo has been sack after such a good record.Especially when I think he had 2cope with Terry scandals. #harsh" - Everton striker Louis Saha.
"Rafa Benitez will just not be accepted by Chelsea supporters, neither will Avram Grant or Harry Redknapp. I simply don't think Benitez is a good manager. He's been out of work for two years now, if he was any good why hasn't any club snapped him up?" - Chelsea Supporters Group chair Trizia Fiorellina.
“The sacking of Chelsea manager Roberto Di Matteo demonstrates, not decisive leadership, but knee jerk authoritarianism. From a leadership perspective, this sacking is highly questionable. Yes, in the world of football, as in business, sometimes things don't go the way we want, but a short-term view of life can end up being counterproductive to both long-term performance and revenue generation. Given the performance Di Matteo has delivered and the chance a "bad patch" was always on the cards, a more tolerant approach would have made common sense. This unplanned departure now leaves the club rudderless at a critical time and presents a significant challenge in finding a new successor. Who would accept such a role with the chance of being sacked in the middle of the night? This event just goes to confirm the significant dangers of command and control leadership.” - Professor Chris Roebuck, a leadership expert at Cass Business School in London.