John Carew, Julien Faubert, Abdoulaye Faye, Papa Bouba Diop, Frank Nouble and Olly Lee are all set to leave the club when their deals expire in June.
Faubert, who joined the Hammers in 2007, is jettisoned despite playing 34 games in 2011-12, including Saturday's play-off final win against Blackpool.
Neither Carew or Diop have started a game since January, while Faye's last appearance came back in April in the 3-3 draw with Birmingham at Upton Park.
Fellow striker Nouble has also been released after spending the majority of the season on loan with Gillingham, failing to impress on his only Hammers appearance on New Year's Eve against Derby.
An offical statement on the club's official website website read: "Julien Faubert, Abdoulaye Faye, Papa Bouba Diop, John Carew, Frank Nouble and Olly Lee will all leave West Ham when their current contracts expire on June 30.
"The six professionals have all played their part in a successful 2011-12 season which saw the Hammers gain promotion back to the Premier League.
"West Ham would like to thank all of the aforementioned players for their hard work and dedication and wish them luck in their future careers."
Midfielder Henry Lansbury has also left the club and returned to Arsenal after his season-long loan came to an end.