A semiconductor device may include a substrate including an NMOS region and a PMOS region, and having a protrusion pattern; first and second gate structures respectively formed on the NMOS region and the PMOS region of the substrate, crossing the protrusion pattern, and extending along a first direction that is parallel to an upper surface of the substrate; first and second source/drain regions formed on both sides of the first and second gate structures; and first and second contact plugs respectively formed on the first and second source/drain regions, wherein the first contact plug and the second contact plug are asymmetric. Methods of manufacturing are also provided.