In this study, the vibration analysis of a laminated composite magnetorheological elastomer (MRE) sandwich beam is presented. The governing differential equations of motion of a sandwich beam embedding a MRE layer as core layer and laminated composite beams as the face layers are presented in a finite element formulation. The validity of the developed finite element formulation is demonstrated by comparing results in terms of the natural frequencies derived from the present finite element formulation with those in the available literature. Various parametric studies are also performed to investigate the effect of a magnetic field on the variation of the natural frequencies and loss factors of the MR elastomer composite sandwich beam under various boundary conditions. Furthermore, the effect of the thickness of the MR elastomer layer on the variation of the natural frequencies and loss factors are studied. The study suggested that the natural frequency increases with increasing magnetic field, irrespective of the boundary conditions.