The 22-year-old midfielder has put pen to paper on a contract, that will keep him at Stamford Bridge until the summer of 2031.
The Blues revealed on Saturday that they were on verge of completing terms with the attacker.
“I’m so happy to sign for Chelsea,” the Ukrainian told the club’s official website.
“This is a huge club, in a fantastic league and it is a very attractive project for me at this stage of my career. I’m excited to meet my new teammates and I’m looking forward to working and learning under Graham Potter and his staff.”
Graham Potter’s side announced the deal during their Premier League game against Crystal Palace at Stamford Bridge.
Mudryk has scored 10 goals and provided eight assists in 18 appearances across all competitions this season.
The winger could make his debut for Chelsea during a Premier League match against Liverpool at Anfield next weekend.