A vertical memory device includes a lower circuit pattern on a substrate, a plurality of gate electrodes spaced apart from another in a first direction substantially perpendicular to an upper surface of the substrate on the lower circuit pattern, a channel extending through the gate electrodes in the first direction, a memory cell block including a first common source line (CSL) extending in a second direction substantially parallel to the upper surface of the substrate, and a first contact plug connected to the lower circuit pattern and the first CSL and overlapping the first CSL in the first direction.