Birmingham have confirmed the release of Kevin Phillips, Sebastian Larsson and Lee Bowyer following the club's relegation from the Premier League.
Also leaving are goalkeeper Maik Taylor, defender Martin Jiranek and full-back Stuart Parnaby.
All six players have left the club on the expiry of their contracts.
Blues confirmed taking up the option of a one-year contract extension for Stephen Carr, while Enric Valles has also signed a new one-year deal.
The Spanish midfielder missed most of last season with a foot injury following his arrival from Dutch side NAC Breda.
The club also said that discussions over a new contract are ongoing with Scotland forward James McFadden, who also missed most of last season with a knee injury.
Birmingham were relegated to the Championship on the last day of the Premier League season after losing 2-1 at Tottenham, which meant they finished third from bottom.
"We have discussed strategies and player movements and policies," said Birmingham's acting chairman Peter Pannu.
"Suffice to say there is by and large consensus in the way we believe we should proceed."