A method of manufacturing a phase change memory device includes forming a lower electrode layer pattern and an insulating interlayer covering the lower electrode layer pattern, forming a first opening in the insulating interlayer to expose the lower electrode layer pattern, forming an oxide layer pattern on the sidewall of the first opening and a lower electrode under the oxide layer pattern by partially removing the oxide layer and the lower electrode layer pattern, forming an insulation layer filling a remaining portion of the first opening, removing the oxide layer pattern by a wet etching process to form a second opening, and forming a phase change material pattern on the lower electrode such that the phase change material pattern fills the second opening.