We examined white matter volumes in four prefrontal subregions using structural magnetic resonance imaging in 10 pathological liars, 14 antisocial controls, and 20 normal controls. Liars showed a relatively widespread increase in white matter (23-36%) in orbitofrontal, middle and inferior, but not superior, frontal gyri compared with antisocial and normal controls. This white matter increase may predispose some individuals to pathological lying.