Middlesex have opted against renewing the contracts of Scott Newman, Anthony Ireland and Robbie Williams for the 2013 season.
Opening batsman Newman played 28 first-class, 24 List A and 26 T20 matches for Middlesex and scored almost 3,000 first team runs since joining the club for the 2010 season.
Pace bowler Ireland has represented Middlesex just 20 times since arriving at Lord's from Gloucestershire in 2011.
Medium pacer Williams has been with the county since 2005 and joined full-time in 2010 after finishing his studies at Durham University.
Commenting on the departure of Newman, Ireland and Williams Middlesex managing director of cricket, Angus Fraser, said: "Terminating a player's association with Middlesex is not a pleasant experience for both parties and Middlesex would like to thank Scott, Anthony and Robbie for the effort and commitment they have shown the Club during the time they have been with us.
"Each has stated a desire to continue their careers in cricket and everyone at Middlesex wishes them luck and success in the future."