The importance of the inclusion of disk flexibility on the natural frequencies in a rotor dynamic analysis has attracted the attention of many researchers in the recent past. Such an analysis helps to predict the dynamic response of rotors more accurately from the natural frequencies and mode shapes calculated hence. In the present analysis a semi-analytical conical shell finite element is used for the modelling of the rotor with the inclusion of the support bearing flexibility. Such an element could include the flexibility of the disks, shaft and the bearings. A parametric study was also performed for looking into the frequency characteristics of the system. The study brings out the additional disk modes a well as the behaviour of the system at higher circumferential modes. Copyright © 1996 Elsevier Science Ltd.