A semiconductor device includes an active region having a doped region, a first contact member on the doped region, gate structures including a first gate structure having a first gate and a second gate structure having a second gate, the first and second gate structures being adjacent to each other and on opposite sides of the first contact member, an interlayer dielectric layer on the active region and surrounding the first and second gate structures, and the first contact member, a first insulator layer on a portion of the interlayer dielectric layer, a first contact on an upper surface of the first gate and a second contact on an upper surface of the second gate, and a second insulator layer surrounding the first and second contacts each having an upper surface lower than an upper surface of the second insulator layer.