Batsmen Luke Wells and Harry Finch will leave Sussex at the end of the season.
The pair, who have 17 years of first-team experience at Hove between them, have not had their contracts renewed.
Wells, 29, has scored more than 7,500 first-class runs and taken 79 wickets, and played 176 games in all formats for the county since his debut in 2010.
Finch, 25, has amassed more than 3,000 runs in 112 appearances in red and white-ball cricket since featuring for the first time in 2013.
"Harry's in the squad to bat and probably didn't quite get the runs that he would have liked," said head coach Jason Gillespie, who is also leaving Hove at the end of the season.
"We hope Harry can continue his career and genuinely wish him all the very, very best in his career going forward. I look forward to seeing him doing well in the future."
Wells' name is a familiar one at Sussex, with his father Alan and uncle Colin both having played for the club.
"We gave some opportunities to some other players in the Bob Willis Trophy which Luke was obviously disappointed about, and it's been a tough year for a lot of players," Gillespie told the club website.
"Luke falls into that category, there's no doubt about that. Unfortunately, there's just not a spot in the squad for him moving forwards."