Care, 35, will extend a 16-year-career with Quins, having made 321 appearances since joining from Leeds and become the club’s record try scorer.
The latest contract announcement by the reigning Gallagher Premiership champions follows the likes of full-back Tyrone Green also agreeing new contract terms.
Care, capped 84 times by England over a 10-year international career, said: “I’m delighted to sign on again with Quins. I love playing for this club.
“Since I came down here 16 years ago I’ve loved every minute of playing at The Stoop, our fans are the best out there and it’s been incredible to have them back in full voice this season.
“I’ve made some great friends and incredible memories in this jersey and I can’t wait to make some more.”
Harlequins attack and backs coach Nick Evans is confident there is still plenty more to come from Care, who captained Quins during the 2015-16 and 2016-17 campaigns.
“Danny is central to so much we do as Harlequins both on and off the field and epitomises the way we play,” Evans said on the Harlequins website.
“I’m fortunate to have played with Danny for nine years in this jersey and worked with him as a coach for five seasons.
“He is a unique, extremely talented individual and we’re thrilled to have him recommit to the team as we look to become the most admired club in Europe.”
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