A semiconductor device includes a plurality of active patterns protruding from a substrate, a gate structure intersecting the plurality of active patterns, a plurality of source/drain regions respectively on the plurality of active patterns at opposite sides of the gate structure, and source/drain contacts intersecting the plurality of active patterns, each of the source/drain contacts connected in common to the source/drain regions thereunder, each of the plurality of source/drain regions including a first portion in contact with a top surface of the active pattern thereunder, the first portion having a width substantially increasing as a distance from the substrate increases, and a second portion extending from the first portion, the second portion having a width substantially decreasing as a distance from the substrate increases, bottom surfaces of the source/drain contacts being lower than an interface between the first and second portions.