Claudio Ranieri has left Fulham following the 2-0 defeat to Southampton on Wednesday that sees them 10 points from safety with 10 games remaining, with Scott Parker named as caretaker manager.
Ranieri replaced Slavisa Jokanovic as manager in November but earned only three wins from 16 league matches, with 10 defeats.
"Following our discussion this afternoon, Claudio Ranieri agreed to my decision that a change was in the best interest of everyone," Fulham's American billionaire owner Shahid Khan said. "No surprise to me, Claudio was a perfect gentleman, as always. Claudio's tenure at Fulham didn't produce the outcome we anticipated and needed when I appointed him as Manager in November, but be assured he is not solely to blame for the position we are in today."
Said Ranieri: "I am obviously disappointed with the recent results and that we could not build on the good start we made following my appointment. Finally, I would like to thank the Club, the players and the fans for the support they have given me during my time at the Club."
In welcoming Ranieri, Khan said it was a "risk-free" decision to appoint the man who won the Premier League title with Leicester in 2015-16 and managed Chelsea from 2000 to 2004.
Chants of "You don't know what you're doing" rang out from Fulham's away supporters as Ranieri made second-half substitutions during the team's loss at Southampton on Wednesday.
Later, a banner was unfurled that read: "Risk free? Are you watching Tony Khan?" He is the son of Shad Khan and the club's vice chairman and director of football operations.
When Ranieri took charge, Fulham were bottom and had five points from 12 matches. The team is now 19th and has lost seven of the past eight Premier League games.
Fulham have conceded the most goals in the Premier League this campaign with 63, and their goal difference is the worst in the division.
The club's next fixture is a home clash with local rivals Chelsea on Sunday, before games against Leicester, Liverpool and Manchester City.
Information from The Associated Press was used in this report.