Background. We assessed lateral preference in 80 male patients with combat-related post-traumatic stress disorder (PTSD) and in 100 healthy age-matched male controls.Methods. Hand, foot, eye and ear preferences were examined, using the Edinburgh Handedness Inventory-Modified and the Coren Inventory of Lateral Preference.Results. Mixed lateral preference was noted in significantly more PTSD patients than controls (65 v. 43%, P<0·005).Conclusions. These results indicate a possible hemispheric imbalance (less lateralization) in PTSD patients, with the right hemisphere playing a more active role in perceptual and cognitive processing and in the regulation of biological responses in these patients. This imbalance may be relevant to the pathophysiology of PTSD.