A method of manufacturing a phase change memory device includes forming at least one active device on a substrate, forming a bottom electrode electrically connected to the at least one active device, forming a phase change material layer and a top electrode on the bottom electrode, forming a capping layer on an upper surface of the top electrode and on side surfaces of the top electrode and phase change material layer, removing a portion of the capping layer overlapping the upper surface of the top electrode to define capping layer sidewall portions, forming an interlayer insulation film on the capping layer sidewall portions and on the top electrode, removing a portion of the interlayer insulation film from the top electrode to form a contact hole through the interlayer insulation film, and forming a contact plug in the contact hole.