Memory devices may include a source region, channels, a gate insulation layer pattern, a selection gate pattern, a first gate pattern, a second gate pattern and a drain region. The source region may include first impurities having a first conductivity type at an upper portion of a substrate. The channels may contact the source region. Each of the channels may extend in a vertical direction that is perpendicular to an upper surface of the substrate. The selection gate pattern may be on sidewalls of the channels. The first gate pattern may be on the sidewalls of the channels. The first gate pattern may be a common electrode of all of multiple channels. The second gate patterns may be on the sidewalls of the channels. The drain region may include second impurities having a second conductivity type that is different from the first conductivity type at an upper portion of each of the channels.