The objective of this paper is to develop more accurate procedures in the generation of consistent mass matrices of structural elements which can then be embedded in a usual finite element program. This is accomplished by the use of exact displacement functions for the elements, rather than approximate ones, obtained from the solution of the differential equations governing the free vibration behavior of structural components. At the present time, two types of elements are considered, namely, straight beam and curved (circular arc) beam elements, both of which have a uniform cross section. However, the general concepts developed in this study are equally applicable to other types of elements, such as plate elements. Obviously, when several types of elements are used to model a structure, due care must be exercised in enforcing compatibility between two different classes of elements. The implementation of this procedure in connection with planar straight beam elements has been accomplished leading to the generation of the consistent mass matrix of the element. This matrix is obtained in explicit form resulting in improved computational efficiency. The generation of the mass matrix for the curved beam element is in progress. Based on the improved inertial properties and discrete element techniques, a computer program has been developed for the free vibration analysis of frame type structures. Results have been obtained for various type of structures, including free-free, clamped-free (cantilever) and continuous beams, and simple portal frames. Comparison with exact solutions in these cases indicate that with a relatively small number of elements high accuracy can be achieved in computing the natural frequencies and modes of vibration of these systems. In addition, contrary to other approximate methods, such as the Rayleigh-Ritz method, the present procedure yields very good approximations to higher frequencies.