This research focuses on the free vibration analysis of laminated composite beams using the finite element method. The formulation utilizes an improved first order shear deformation theory, which considers 3D constitutive equations and thickness stretching. The finite element model is derived by the Hamilton's principle and the fundamental field variables are approximated with high-order interpolations functions to avoid shear locking. Applications are done to laminated composite beams. A computational program is implemented in MATLAB. Results are compared with others formulations obtained in the literature to validate the model. A parametric analysis is carried out to study free vibration response under different number layers, layer scheme and fiber orientations. The formulation proved to be quite accurate with very satisfactory resultsulta ser bastante precisa con resultados muy satisfactorios.