The much-travelled Ranieri won the Premier League title with unfancied Leicester City in 2016 and most recently coached French side Nantes.
Italian Claudio Ranieri has been appointed the new manager of Fulham, replacing Slavisa Jokanovic, the struggling Premier League club said on Wednesday.
Serb Jokanovic led Fulham into the top flight from the second-tier Championship via the playoffs last season but the London club have made a poor start and are bottom of the league with one win in 12 games.
Fulham chairman Shahid Khan said he had taken the decision reluctantly but felt a change was needed.
"I wasn’t anticipating having to make this announcement related to Slavisa and wish the circumstances were such that I didn’t have to," Khan said in a statement.
"But our path this season has led me to make what I know is the correct decision, at the right time, for our players, the club and our supporters."
The much-travelled Ranieri won the Premier League title with unfancied LeicesterCity in 2016 and most recently coached French side Nantes.
The 67-year-old has worked with Valencia and Atletico Madrid in Spain, Juventus, AS Roma and Inter Milan in Italy and also had a four-year spell in England with Fulham's neighbours Chelsea.
"Making a change without having the right answer or succession plan was not an option, so having someone of Claudio’s calibre ready to accept our challenge was comforting but, most of all, essential," Khan said.
"Claudio is risk-free and ready-made for the Premier League, and particularly so for what we need at this moment at Fulham.
"His recent body of work with LeicesterCity is literally legendary, and then you look at Claudio's experience with Chelsea and big clubs throughout Europe, and it's pretty evident we are welcoming an extraordinary football man to Fulham Football Club."
Ranieri faces a tough task to turn around Fulham's season and avoid an immediate drop back to the Championship but the Italian said the team was capable of more than just survival.
"It is an honour to accept Mr. Khan's invitation and opportunity to lead Fulham, a fantastic club with tradition and history," Ranieri said.
"The objective at Fulham should never be to merely survive in the Premier League. We must at all times be a difficult opponent and should expect to succeed. This Fulham squad has exceptional talent that is contrary to its position in the table.
"I know this team is very capable of better performances, which we will work on straight away as we prepare for Southampton at the Cottage."