Integrated circuit devices and methods of forming the same are provided. The integrated circuit devices may include a transistor comprising a source/drain region on a substrate; a backside power rail spaced apart from the source/drain region; and a power contact that is between the source/drain region and the backside power rail and electrically connects the source/drain region to the backside power rail. The substrate may be between the source/drain region and the backside power rail, and a centerline in a width direction of the source/drain region is angled with respect to a centerline in a width direction of the power contact.