A semiconductor device includes a first impurity region, a channel pattern, a second impurity region, a gate structure, a first contact pattern, a second contact pattern and a spacer. The first impurity region may be formed on a substrate. The channel pattern may protrude from an upper surface of the substrate. The second impurity region may be formed on the channel pattern. The gate structure may be formed on a sidewall of the channel pattern and the substrate adjacent to the channel pattern, and the gate structure may include a gate insulation pattern and a gate electrode. The first contact pattern may contact an upper surface of the second impurity region. The second contact pattern may contact a surface of the gate electrode. The spacer may be formed between the first and second contact patterns. The spacer may surround a portion of a sidewall of the second contact pattern, and the spacer may contact a sidewall of each of the first and second contact patterns.