We derive and investigate the dispersion relation for accretion disks with retarded or advanced heating .
We follow the \alpha -prescription but allow for a time offset \tau between heating and pressure perturbations , as well as for a diminished response of heating to pressure variations .
We study in detail solutions of the dispersion relation for disks with radiation-pressure fraction 1 - \beta .
For \tau < 0 ( delayed heating ) the number and sign of real solutions for the growth rate depend on the values of the time lag and the ratio of heating response to pressure perturbations , \xi .
If the delay is larger than a critical value ( e.g. , if \Omega \tau < -125 for \alpha = 0.1 , \beta = 0 and \xi = 1 ) two real solutions exist , which are both negative .
These results imply that retarded heating may stabilize radiation-pressure dominated accretion disks .