Di Matteo has signed a two-year contract with the Blues.
The Italian took over as interim manager following the sacking of Andre Villas-Boas in March and guided the Blues to FA Cup and Champions League glory.
A statement from Chelsea chief executive Ron Gourlay read: “Roberto’s quality was clear for all to see when he galvanised the squad last season and helped the club make history, and the owner and board are very pleased he will be continuing his good work.
“We all believed he was a young coach with much to offer when we first asked him to take charge of team affairs in March and the manner in which he worked with us, the players and all the staff, and the success that followed, made him the clear choice when it came to selecting the person to take us forward in the seasons to come.
“We will be working closely with Roberto in the weeks ahead, some exciting signings have already been made and Roberto has had input into those.
“Although he has set the bar very high in the short time he has been in charge, we know that Roberto is the right man to lead Chelsea onto further success.”
Di Matteo told the club’s official website: “I’m obviously delighted to have been appointed as manager and first-team coach. We all achieved incredible success last season that made history for this great club.
“Our aim is to continue building on that and I’m already planning and looking forward to the squad’s return for pre-season.”
