This is coming just six months after announcing the termination of their agreement with Adidas.
The agreement will see Nike become their official kit supplier; produce all matchday, training and exercise kit for the first team, academy and ladies teams, as well as a range of Chelsea fan merchandise.
The deal will begin at the start of the 2017/18 Premier League season.
“This is an incredibly exciting and important deal for the club,” said Chelsea director Marina Granovskaia.
Trevor Edwards, president of the Nike brand, said: “Chelsea is a world-class club with a rich tradition and passionate fans across the globe. The partnership with Chelsea reinforces our leadership position in football. We are excited to help grow the club’s global reach, serving players and supporters with Nike innovation and design.”
Chelsea’s deal is believed to have been negotiated directly with Granovskaia, who is the owner Roman Abramovich’s closest adviser.