A generalized modal approach is presented to solve the equations of motion of a laminated composite beam obtained with a third-order shear deformation theory. The biorthonormal eigenfunctions of the differential equations expressed in the state form are used to decouple the equations. To obtain these eigenfunctions for beams with any arbitrary beam boundary conditions, a method is presented. The solution obtained by this approach is used to calculate the beam response for spatially and temporally correlated random loads. Several sets of numerical results are presented to demonstrate the importance of shear deformations in the dynamic analysis of composite beams.