Vibration behavior of adaptive laminated composite beams integrated with magnetorheological (MR) fluid layer has been investigated using layerwise displacement theory. In most of the existing studies on the adaptive laminated beams with MR fluids, shear strain across the thickness of magnetorheological (MR) layer has been assumed a constant value, resulting in a constant shear stress in MR layer. However, due to the high shear deformation pattern inside MR layer, this assumption is not adequate to accurately describe the shear strain and stress in MR fluid layer. In this work a modified layerwise theory is employed to develop a Finite Element Model (FEM) formulation to simulate the laminated beams integrated with MR fluids. In the present model, each layer is modeled based on First-order Shear Deformation Theory (FSDT). The inter-laminar stresses between face-layer and MR layer is estimated more precise so FEM results are more accurate. Standard test of ASTM E 756-98 was employed to develop an empirical relationship for the complex shear modulus of MR fluid. Numerical examples have been illustrated the effects of MR fluid layer on the vibration behavior of the laminated beam. An experimental setup has been (FSDT) fabricated for the verification of the results.