As reported by Goal.com on Sunday, the club's defeat to Wigan in the FA Cup final proved the last straw for the City owners, who said in a statement that the Italian had failed to achieve any of the team's targets for the season.
The decision comes exactly one year to the day since Sergio Aguero's dramatic late goal saw Mancini's side clinch their first league title for 44 years, with Malaga coach Manuel Pellegrini expected to be unveiled as his replacement at the Etihad Stadium.
|ARE MAN CITY RIGHT TO SACK MANCINI?
|VOTE IN OUR POLL|
"This has been a difficult decision for the owner, chairman and board to make and it is the outcome of a planned end of season review process that has been brought forward in light of recent speculation and out of respect for Roberto and his extensive contributions to the club.
"Despite everyone's best efforts, the club has failed to achieve any of its stated targets this year, with the exception of qualification for next season's Champions League. This, combined with an identified need to develop a holistic approach to all aspects of football at the club, has meant that the decision has been taken to find a new manager for the 2013-14 season and beyond."
Club chairman Khaldoon Al Mubarak declared: "Roberto's record speaks for itself and he has the respect and gratitude of Sheikh Mansour, myself and the board for all of his hard work and commitment over the last three-and-a-half years. He has clearly also secured the love and respect of our fans.
"He has done as he promised and delivered silverware and success, breaking the club's 35-year trophy drought and securing the title in 2012. I would like to personally and publicly thank him for his dedication to the progress that he has overseen and for his support and continued friendship."
Mancini's assistant, Brian Kidd, is to take temporary charge of the team for their final two matches of the Premier League campaign and their post-season friendlies in USA.
As exclusively revealed by Goal.com, the Italian has been approached by ambitious French side Monaco with regards to taking over from Claudio Ranieri following their promotion to Ligue 1.