In this paper, a detailed study has initially been carried out, using SAP2000, to evaluate the adequacy of a griIIage model in refleeting the vibration characteristics of a curved bridge in comparison with the finite element model since the griIIage model is widely used by professional engineers due to its simplicity in modeIIing and interpretation. From this study, it has been noted that the grillage model is not capable of retleeting the dynamic characteristics accurately. In view of this, a finite element formulation and a computer program have been developed using eight noded isoparametric curved quadratic shell finite elements to assess the influence of different parameters, viz., curvature, aspect ratio, on the dynamic response of bridges curved in plan. However, the question of whether or not the deck slab curved in plan should be assumed to be rigid in its pIane during vibration, is yet to be answered. Therefore, the effect of curvature on in-plan deck tlexibility during in-pIane vibration of bridge decks curved in plan is also studied. The parametric study carried out in this investigation to establish the relationship between the structural behaviour of curved bridge deck with that of straight bridge would prove to be very useful for bridge engineers to readily assess the behaviour of bridge decks curved in plan, based on the responses for a straight bridge deck.