The　pole-placement　problem　of　linear　systems　by　state-PID　feedback　is　investigated.　A　general　and　efficient　pole-placement　solution　for　linear　time-invariant　systems　with　state-PID　feedback　is　derived　using　the　traditional　procedures　of　full　state　feedback.　The　principle,　called　Separating　Theorem,　holds　for　pole-placement　by　state-PD,　state-PI　and　state-PID　feedback　and　is　successfully　applied　to　the　control　of　a　robot　vibration　absorber.　These　results　open　a　new　area　for　the　design　and　tuning　of　state-PID　feedback　types　of　controller.　Copyright　©　2006　Inderscience　Enterprises　Ltd.