The 31 year old was unlucky at Stamford Bridge this season and, with his contract expiring in June, he left for the French championship.
Fabregas joined Chelsea from Barcelona in 2014 and was initially a key player for Jose Mourinho and Antonio Conte, winning the Premier League title under both
However, the arrival of Maurizio Sarri before 2018-2019 effectively marked the end of the Chelsea career of Fabregas, as the Italian brought in his former Naples midfielder Jorginho
The transfer eventually leads to the long collaboration of Fabregas with English football , at least for the time being, having played 501 times for Arsenal and Chelsea.
"It is a great pleasure to join the AS Monaco, a new project for me," said Fabregas. "The group is of quality with young players and a young coach.
" I'm here to help the team, I do not see the time to start, we have a great game to play on Sunday in Marseille. I'm very excited. "
Fabregas' move also sees him reunite with former teammate of the Gunners Thierry Henry.
Henry spoke at a press conference confirming his interest in Fabregas, who claims to have spoken with" three times a week since 2007 "when the Frenchman left Arsenal for the Boat.
Vice-President Vadim Vasilyev added:" We are very pleased to welcome AS Monaco Cesc Fabregas, a top-level player world and a great professional, whose arrival shows the club's ambition.
"This is obviously an excellent technical reinforcement for the team, but we are convinced that his experience at the highest levels will bring a lot to our players on and off the pitch."
Monaco We hope that the signature of Fabregas can provide the necessary spark to help them avoid the decline.
Henry's team is second from the bottom in Ligue 1