The semiconductor device includes a substrate comprising first and second regions, in the first region, first and second gate electrodes formed parallel to each other on the substrate, and being spaced apart from each other by a first distance, in the second region, third and fourth gate electrodes formed parallel to each other on the substrate, and being spaced apart from each other by a second distance which is greater than the first distance, in the first region, a first recess formed on the substrate between the first and second gate electrodes, in the second region, a second recess formed on the substrate between the third and fourth gate electrodes, a first epitaxial source/drain filling the first recess and a second epitaxial source/drain filling the second recess, wherein an uppermost portion of an upper surface of the first epitaxial source/drain is higher than an uppermost portion of an upper surface of the second epitaxial source/drain.