"As of today the contract of Juande Ramos was terminated by mutual consent," CSKA said on their website.
The former Real Madrid and Tottenham Hotspur manager lasted only six weeks at the army club after replacing Brazilian Zico, who was fired following a string of poor results in September.
Former FK Moscow and Krylya Sovietov Samara coach Leonid Slutsky, 38, has taken over from Ramos on a three-year contract, CSKA president Yevgeny Giner said.
Giner hired the experienced Spaniard, who won back-to-back UEFA Cups with Sevilla in 2006-07, to lead them to the Champions League knockout round for the first time.
His arrival paid immediate dividends, with 3-0 league wins over Samara and Dynamo Moscow, but soon after CSKA were back to their usual stuttering form both domestically and in Europe.
UNITED DEFEAT
Last week they dropped points at struggling Spartak Nalchik before a lacklustre 1-0 Champions League Group B defeat at home to Manchester United left the Moscow club in danger of missing out on the knockout round.
CSKA's patience finally ran out with Ramos after his team were soundly beaten by modest city rivals FK Moscow, going 3-0 down before halftime.
The defeat effectively ended their title hopes as they dropped 10 points behind league leaders Rubin Kazan with just four games remaining.
CSKA were jeered off the pitch by their own fans, considered one of the most loyal in Russian soccer and several players needed police protection from the angry crowd after the game.
The 54-year-old Ramos was sacked almost exactly a year ago by Spurs before taking over as Real Madrid coach in December until the end of last season.
