According to example embodiments of inventive concepts, a non-volatile memory device includes a substrate including a second impurity region crossing a first impurity region, and channel regions extending in a vertical direction on the substrate. Gate electrodes may be separated from each other in a vertical direction and a horizontal direction along outer walls of the channel regions. A first insulating interlayer may be on the gate electrodes and the channel regions, where the first insulating interlayer defines a contact hole between at least one adjacent pair gate electrodes and a contact plug is formed in the contact hole to be electrically connected to the second impurity region. An etch stop layer pattern may be on the contact plug and the first insulating interlayer.