A semiconductor device includes a first active fin protruding from a substrate, a first gate pattern covering a side surface and a top surface of the first active fin, and first source/drain patterns at opposite sides of the first gate pattern, each of the first source/drain patterns including a first lower side and a second lower side spaced apart from each other, a first upper side extended from the first lower side, a second upper side extended from the second lower side. The first lower side may be inclined at a first angle relative to a top surface of the substrate, the second upper side may be inclined at a second angle relative to the top surface of the substrate, and the first angle may be greater than the second angle.