The 24-year-old Wales international openside flanker's future had been in doubt with several clubs believed to be interested in signing him as his contract edged towards expiring at the end of this campaign.
But Jenkins, who has made 83 appearances for the Blues since making his debut in 2011, has opted to follow on from fellow academy products Lloyd Williams and Macauley Cook by agreeing fresh terms at Arms Park.
"I'm really happy to sign a new contract here. I've come through the Cardiff Blues system, it's a region I'm very passionate about and I'm really optimistic about the future," he said on the club's website.
"It's been great seeing so many of the other boys signing new deals and you only need to look at the likes of Dillon Lewis, Seb Davies and Owen Lane to see the talent coming through.
"I feel this is the best environment for me to continue improving and the competition for places in the back-row can only be beneficial to us all.
"I'm now looking forward to getting back on the pitch and contributing as much as I can in the second half of the season."