The Chelsea captain has added another two years to his west London stay, thwarting Barcelona's long-running pursuit of the 32-year-old.
The Spain full-back joined Chelsea from Marseille in 2012 and has swept the board of major club trophies since, with the 2021 Champions League and 2022 Club World Cup completing the set.
The long-serving defender automatically triggered a one-year addition to his Chelsea deal at the back-end of last term, but has now committed to a more lasting extension to his Stamford Bridge tenure.
Boss Thomas Tuchel was understood to be determined to retain Azpilicueta in light of Toni Rudiger and Andreas Christensen's departures, especially given the experienced Spaniard's leadership and influence at the Blues.
"I am really happy to extend my stay at Chelsea, my home," said Azpilicueta.
"It is almost 10 years since I first arrived and joined the club, so I really feel the love and I am really excited for the new project we have in our hands.
"I would like to say thank you to (Chelsea owners) Todd (Boehly) and Behdad (Eghbali) for giving me the opportunity to keep my journey at this amazing club and I really looking forward to continuing our adventure.
"I am a really proud captain and I hope we can share many good memories together."
Azpilicueta's decision to commit to Chelsea will prove a major boost to manager Tuchel, with the Blues continuing to reshape both their defence and overall squad.
Kalidou Koulibaly's arrival adds genuine quality, steel and nous at centre-back, but Azpilicueta's leadership and Premier League experience remain highly prized commodities by Tuchel.
Chelsea will continue to push to sign Marc Cucurella from Brighton, with Levi Colwill still likely to head in the other direction, either on loan or permanently.
The Blues are understood to harbour interest in Southampton's Kyle Walker-Peters too.
Leicester's Wesley Fofana is another target for Chelsea, but the Foxes' valuation of £80million and above could prove prohibitive.
Azpilicueta's new deal will relieve an edge of pressure on the Blues' recruitment, especially if Marcos Alonso goes on to complete his own long-mooted move to Barcelona later this summer.
"We are so happy that Cesar is staying at Chelsea for a minimum of two more years," said Chelsea chairman and co-controlling owner Boehly.
"We are thrilled with our captain showing his exemplary commitment and leadership yet again. There is still so much to do together."