Derby have decided not to offer Jeff Kenna, Pablo Mills and Kevin Poole fresh deals at Pride Park when their contracts expire in the summer.
Defender Kenna has 27 caps for Republic of Ireland
"Jeff, Pablo and Kevin have been great servants to Derby County," managing director Mike Horton said.
"I am sure the supporters will join the club in wishing them all the best for the future."
Defender Kenna, 35, made 72 appearances for the Rams after joining from Birmingham in March 2004.
Mills, 21, a product of the club's academy, made 64 appearances while goalkeeper Poole, 42, turned out on seven occasions for the Championship side.