A steam turbine blade is a very complex structure. Apart from geometric complexities like variation of twist, taper, width and thickness along its length, the blades are attached to a disc, which also contributes to their dynamic behavior in a significant way, depending upon the dimensions. Besides, the blades are coupled by means of a lacing rod, lacing wire or shroud and also through a flexible disc. These coupled modes can also be a source of resonance for the blades and are not easily predicted by conventional methods. Finite element analysis using the principle of cyclic symmetry can effectively predict the modes corresponding to all the circumferential wave numbers of vibration of a bladed disc system. In this paper, the results of dynamic analysis of the third stage of the High Pressure Side (H.P.-3) and fifth stage of the Low Pressure Side (L.P.-5) of a 235MWsteam turbine have been presented. Experimental findings, wherever possible, have been reported. © Krishtel eMaging Solutions Private Limited.