A semiconductor device includes a first active region that extends on a substrate in a first direction, a second active region that extends in parallel with the first active region, an element isolation region between the first and second active regions, a gate structure that extends in a second direction different from the first direction, and intersects the first and second active regions, a lower contact spaced apart from the gate structure in the first direction, the lower contact being on the first active region, the element isolation region, and the second active region, and an upper contact on the lower contact between the first active region and the second active region. A width of the lower contact in the first direction that is on the first active region m narrower than a width of the lower contact in the first direction that is on the element isolation region.