Abstract: Truncated conical shells are extensively used in space crafts, robots, shelters, domes, tanks and in machinery or devices. Thus, the study of their vibrational characteristics has long been of interest for the designers. Moreover, because of the need for light weight designs, composite shell materials have become more and more common. One of the advantages of composite materials is that one can design directional properties into them almost on demand. The purpose of this study was to analytically investigate the vibrational behavior of composite conical shells. Based upon the thin shell theory, the governing equations of motion were derived. The Galerkin method along with beam mode shapes such as weighting functions was employed. The boundary conditions were expected to significantly affect the mechanical behavior of shell-type structures and making use of the beam modal functions made it possible to examine their role in the mechanical behavior of conical shells. The results of the present study, which were in excellent agreement with the existing data from the literature, indicated the considerable effect of boundary conditions on the natural frequencies of shells.