The world's number two Test batsman has committed himself to Headingley until December 2019.
Root will play his final County game for Yorkshire on Sunday against Surrey before joining the England squad for their first Test against Sri Lanka, which begins on May 19.
"I'm delighted to be committing my future to Yorkshire," Root told club's website. "Even though I don't play as much as I would like for Yorkshire these days due to my international commitments, I still get a huge buzz wearing the white rose on my cap and representing my county. I couldn't see myself playing cricket for any other county.
"Yorkshire have given me a great education and foundation as a cricketer and without the support of the players and coaches at Headingley I wouldn't be in the position I'm in today with England.
"The club have a huge summer ahead looking to be crowned County Champions for a third successive year and I wish the lads every success in the world in trying to achieve their dreams. It would be a monumental effort."
Root joined Yorkshire in 2009.