In this study, the free vibration responses of the laminated composite beams with varying cross-section formulated by considering the cross sectional variation along longitudinal (thickness) and transverse (width) directions of the beam are investigated. The governing differential equations of motion of the various taper models of rotating laminated composite beams with varying section are presented in the finite element formulation based on higher order shear deformation theory (HSDT) including the rotating effects such as centrifugal force and pre-stress. The finite element formulation developed for the free vibration analysis of non-uniform laminated composite beams is validated by comparing the natural frequencies evaluated using the present finite element method (FEM) with those obtained from the experimental measurements. Various parametric studies are also performed to study the effect of taper models, rotational speed and ply orientation on the dynamic characteristics of the composite beam with varying section. It was concluded that significant variation in natural frequencies could be yielded by tapering both in the thickness and width directions of laminated composite beam. It was also concluded that the natural frequencies of the non-uniform composite beams can be altered by tailoring or dropping off the plies to fulfil the design requirements of rotating components. © 2016, Springer-Verlag France.