The Real Madrid coach has been heavily linked with a move back to his old club at the end of the season.
"Everyone at Chelsea has good memories of Mourinho," ESPN quotes Ancelotti as saying.
"He did a good job - everyone loves him. When I was at Chelsea, I understood that there was a very good feeling with Mourinho. If he goes back, it'll be very good for everyone."
Ancelotti was in charge of Chelsea between 2009 and 2011 and won the Premier League and the FA Cup.