Provided is a method of fabricating a semiconductor device. The method includes providing a substrate including a transistor area and a resistor area, forming dummy gate structures on the substrate in the resistor area, and a lower interlayer insulating layer; forming a resistor structure having a buffer insulating pattern, a resistor element and an etch-retard pattern disposed sequentially on the lower interlayer insulating layer; and forming resistor contact structures configured to pass through the etch-retard pattern and to contact with the resistor element.