The 21-year-old Ecuador midfielder has signed an eight-year contract at Stamford Bridge with the option to extend for a further season.
Liverpool agreed a £111m deal Brighton to sign Caicedo last week but Chelsea remained his preferred option.
Caicedo made 43 appearances last season as Brighton finished sixth in the Premier League to qualify for the Europa League.
On completing his move to Chelsea, Caicedo said: ‘I am so happy to join Chelsea! I am so excited to be here at this big club and I didn’t have to think twice when Chelsea called me, I just knew I wanted to sign for the club. It’s a dream come true to be here and I can’t wait to get started with the team.’
Co-sporting directors Laurence Stewart and Paul Winstanley said: ‘Moises has proved himself as a standout player in European football over the past 18 months, and we are thrilled to add him to Mauricio Pochettino’s squad.
‘Moises possesses a rare midfield skill set and is a player we've been targeting for some time. We believe he will make a significant impact at Stamford Bridge this season – and in the years ahead.’
