Former England fast bowler Sajid Mahmood is to leave Essex along with leg spinner Tom Craddock, while batsman Nick Browne has signed a new two-year contract.
Mahmood, 32, played eight Tests and 30 limited-overs matches for England, scoring a Test highest of 34 and taking 53 wickets for his country.
Cousin to boxer Amir Khan, Mahmood signed for Essex from his native Lancashire at the start of last season.
Craddock joined Essex from the Unicorns three years ago and the 25-year-old's highlights include taking five for 69 in the LV= Challenge match against England at Chelmsford in 2013.
Essex head coach Paul Grayson told his club's official website, essexcricket.org.uk: "It's always a difficult time of year when releasing players.
"Both players have given Essex 100 per cent during their time at the club. Both have been excellent professionals and we would like to thank them for their contribution. We wish them all the best for the future."
But there was better news for Browne, who has been rewarded for some encouraging performances this season.
The 23-year-old, who made his Essex debut against Worcestershire in the 2013 County Championship, has hit three centuries in 11 first-class matches this season.
“I’m delighted that Nick has committed a further two years to the club," said Grayson.
"He has been here for many years now playing in the age groups and this year he has come on leaps and bounds to become an important player for us in first-class cricket.
“Nick has secured his place in the team as our opening batsman and has proven that he is an exciting talent after a number of impressive performances this season.”
Browne averages 42.25 from his 20 innings to date for Essex.