Abstract: Disclosed are a semiconductor device having a vertical trench gate structure to improve the integration degree and a method of manufacturing the same. The semiconductor device includes an epitaxial layer having a second conductive type on a first conductive type substrate having an active region and an isolation region, a trench in the isolation region, a first conductive type first region in the epitaxial layer at opposite side portions of the trench, an isolation layer at a predetermined depth in the trench, a gate insulation layer along upper side portions of the trench, a gate electrode in an upper portion of the trench, a body region in the active region, a source electrode on the body region, a source region in an upper portion of the body region at opposite side portions of the gate electrode, and a drain electrode at a rear surface of the substrate.