Integrated circuit devices are provided. The devices may include first and second fin-shaped channel regions protruding from a substrate, and the first and second fin-shaped channel regions may define a recess therebetween. The devices may also include an isolation layer in a lower portion of the recess. The isolation layer may include a first stress liner extending along a side of the first fin-shaped channel region, a second stress liner extending along a side of the second fin-shaped channel region and an insulation liner between the first stress liner and the side of the first fin-shaped channel region and between the second stress liner and the side of the second fin-shaped channel region. The devices may further include a gate insulation layer on surfaces of upper portions of the first and second fin-shaped channel regions and a gate electrode layer on the gate insulation layer.