Prop Tomas Francis and centre Sam Hill have signed new deals with Exeter.
Francis, 23, who joined Exeter in 2014, has agreed a deal until 2017.
The former London Scottish and Doncaster prop is in the Wales World Cup squad and won his first cap in a warm-up win over Ireland.
Hill, 22, has made 36 appearances for the Premiership club since breaking into the team from the Chiefs' academy in 2013 and has agreed to stay at Sandy Park until 2018.
"Tom has had one hell of a year," Exeter head coach Rob Baxter said.
"He did very well in the Premiership for us and has been noticed by international coaches. He's taken each step as it has come and I am really pleased for him.
"We want to progress with him as well so we have moved pretty quickly to extend his contract and that is what you have to do as a club.
"Tom signed for us from a Championship club and has outgrown the contract he signed with us.
"From a club perspective, you want to keep that quality together for an extended period. I am a firm believer in when you have the players you want, you don't want to go changing things."
Hill was a virtual ever-present for Exeter at centre last season and formed an impressive partnership with England's Henry Slade.
"Of all the players who are starting to get talked about and winning international recognition, Sam is probably the most underrated," Baxter said.
"To have him tied to the club for the next three seasons is fantastic. Those are the things you want to hear about a club developing - that your best young players are committed to the club.
"He really wants to stay here and be part of the club going forward and that is fantastic for us. It is a great reward for Sam, who has just kept improving and playing well for us. He is a strong character in the group too."