A duty ratio correction circuit for correcting a duty ratio of a clock signal. The duty ratio correction circuit includes an asymmetry buffer that receives a clock signal and adjusts a duty ratio of the clock signal in response to control signals; a clock generating circuit that i s connected to the asymmetry buffer and detects the duty ratio of the clock signal; and a controller that generates the control signals according to the duty ratio of the clock signal. An operation of the controller is recorded as a program on a computer-readable recording medium.