Abstract: A semiconductor device includes: an active pattern extending in a first direction across an underlying substrate, a gate structure extending in a second direction, on the active pattern, a first source/drain contact electrically connected to a source/drain region within the active pattern, on one side of the gate structure, and a first via pattern electrically connected to an upper surface of the first source/drain contact. A rail pattern is provided, which extends in the first direction, and is spaced apart from the first via pattern in the second direction. A wiring pattern extends in the first direction, and is electrically connected to an upper surface of the rail pattern. The first source/drain contact includes a first recess therein, which is more recessed downwardly relative to the upper surface of the first source/drain contact, and at least a portion of the first recess extends adjacent to the rail pattern.