Ranieri was hired in October to replace Xisco Munoz after the Spaniard’s dismissal.
But the 70-year-old Italian was unable to improve Watford’s fortunes, with the Hornets taking just seven points during his brief reign.
Just 112 days after his appointment, Ranieri paid the price for Watford’s slump into the relegation zone following last week’s 3-0 defeat against relegation rivals Norwich.
“Watford Football Club confirms the departure of Head Coach Claudio Ranieri,” a club statement said.
Watford are second bottom of the table, two points from safety, after losing seven of their last eight league games.
They are without a victory in nine games in all competitions, their longest winless run since 2013.
Watford’s owners, the Pozzo family, felt they had to act now to give the team a chance as they battle to avoid relegation after last season’s promotion from the Championship.
“The Hornets’ Board recognises Claudio as a man of great integrity and honour, who will always be respected here at Vicarage Road for his efforts in leading the team with dignity,” the statement said.
“However the Board feels that, with nearly half of the Premier League campaign remaining, a change in the Head Coach position now will give a new appointment sufficient time to work with a talented squad to achieve the immediate goal of retaining Premier League status.
“No further club comment will be made until this new appointment is confirmed in due course.”
Ranieri famously won a fairytale Premier League title with Leicester in 2016, but his spells in the English top-tier have been far less successful since then.
At Fulham, he was axed after just 106 days in charge in 2019, with the club eventually relegated from the Premier League after his dismissal.
Ranieri’s Watford reign started ominously after Liverpool thrashed them 5-0 in his first game.
Amid talk of player unrest at his methods, Watford’s 4-1 win against Manchester United in November was Ranieri’s second and final victory with the club.
The former Chelsea boss departed Vicarage Road having lost 11 of his 14 matches.
Since Javi Gracia’s exit in 2019, Watford have now sacked further five managers.
The Hornets are looking for their 15th manager since the Pozzo family bought the club in 2012.
Watford will hope to have a new manager in place in time for their crucial showdown at fellow strugglers Burnley on Feb 5.
They have been linked with Diego Martinez, a Spaniard who left his job as Granada boss last May.
New deal for Frank
Meanwhile it was better news at Brentford as their boss Thomas Frank signed a new contract running until 2025, the Premier League club announced yesterday.
The 48-year-old Dane, who was previously assistant head coach under Dean Smith, took charge at the London club in October 2018.
He guided them to promotion last season via the Championship play-offs and they are currently 14th in the Premier League table.
Frank said in a video message on Brentford’s official Twitter feed that he felt privileged to “continue this fantastic journey”.
“We created a lot of Brentford history. I’m looking forward to doing my best every single day to try to create some new history with all the fantastic people at the club,” he added.
Frank’s assistant, Brian Riemer, has also signed a new deal.
"They have been integral to the success that we’ve shared over recent seasons, culminating in achieving our shared target of playing in the Premier League," said the club’s director of football, Phil Giles.
"We want to continue to take Brentford forward, to compete with clubs far bigger than us, and to see how far we can progress."
“They have been integral to the success that we’ve shared over recent seasons, culminating in achieving our shared target of playing in the Premier League,” said the club’s director of football, Phil Giles.
“We want to continue to take Brentford forward, to compete with clubs far bigger than us, and to see how far we can progress.”