In a circuit and method of controlling the horizontal and vertical screen sizes of a cathode ray tube (CRT) monitor, the circuit includes a horizontal screen size compensation circuit, an east-west correction signal controller, a vertical screen size compensation circuit, and a vertical screen size correction signal controller. The horizontal screen size compensation circuit compares the voltage value of a horizontal screen size correction signal with the voltage value of a horizontal reference voltage to obtain first and second horizontal current signals. In response to a horizontal control signal, the horizontal screen size compensation circuit outputs a horizontal correction current signal obtained by subtracting a horizontal variable current signal from the first horizontal current signal. The vertical screen size compensation circuit compares the voltage value of a vertical screen size correction signal with the voltage value of a vertical reference voltage to obtain first and second vertical current signals. In response to a vertical control signal, the vertical screen size compensation circuit selects one of first and second vertical correction current signals and outputs the selected signal as a vertical correction current signal.