Significant structural damages due to pounding between adjacent superstructures of multispan reinforced concrete (RC) highway bridges have been observed in past eanhquakes. Different methods have been proposed in the literature to mitigate the adverse seismic pounding effects. This paper presents an analytical investigation on the use of magnetorheological (MR) dampers in reducing seismic pounding elIects of base-isolated multi-span RC highway bridges. It has been observed that MR damper can elIectively reduce tbe seismic pounding elIect. Three control strategies (passive off, passive on, and bang bang control) of MR damper have been investigated. Although all the conlrol strategies are found to be elIective, bang bang control has been observed to be the most effective.