An integrated circuit includes a standard cell including a first active region extending in a first direction and having a first width, and a filler cell including a second active region of a same type as that of the first active region and being adjacent to the standard cell in the first direction, the second active region extending in the first direction and having a second width which is greater than the first width, wherein the standard cell further includes a first tapering portion of the same type as that of the first active region, the first tapering portion being arranged between the first active region and the second active region.