Keane won 28 and lost 28 of his 81 games in charge of the Tractor Boys since taking over from Jim Magilton. In a statement issued by The League Managers Association, Keane said: "I'm hugely disappointed to be leaving Portman Road.
"Results haven't been as good as I'd have hoped so far this season and when results aren't good the manager gets the sack, that's the game.
"However, I have a genuine belief we were making progress and that the players have what it takes to turn this season around.
"We were preparing well for our visit to Chelsea on Sunday and then our Carling Cup semi with Arsenal. Getting to that semi proves what I know the team is capable of.
"I was also working hard to build the squad during the transfer window, looking at our options to attract new players to the club. I have loved my time at Ipswich, living locally to the club with my family, and have a massive respect for the club, its staff, the fans and the community and I wish them well."
Source: PA
Source: PA