The aim of the study was to investigate the effect of unilateral brain lesions on the perception of subjective contours. Brain damage resulted in a reduced ability to perceive the illusion. The effect, however, was hemisphere and sex dependent. In women an illusion decrement due to either the left or right hemisphere damage was observed, while in men only right hemisphere damage caused a decrement. No specific effect of intrahemispheric localisation of lesion was found. We conclude that mechanisms contributing to subjective contour perception are right hemisphere dependent in males whereas in females they are bilaterally represented.