A semiconductor memory device that includes at least a lower contact plug on a semiconductor substrate, a magnetic tunnel junction of the lower contact plug, and a barrier pattern on a sidewall of the lower contact plug may further include an insulation pattern on the sidewall of the lower contact plug. The insulation pattern may be between the barrier pattern and the magnetic tunnel junction pattern. The insulation pattern may include an upper portion and a lower portion whose width is greater than a width of the upper portion.