We assessed whether a relationship exists between posttraumatic stress disorder (PTSD) and two quantitative aspects of war trauma: the duration of exposure to combat (expressed in months) and the intensity of combat (measured by ratings on the Laufer Combat Scale). These stressor characteristics were measured in relation to PTSD prevalence and persistence. Eighty-four veterans, inducted during the Vietnam War, who attended an orthopedic clinic participated in the study. A significant association was found between duration of combat exposure and prevalence and persistence of PTSD. The longest duration of combat exposure was found in patients who still suffered from PTSD. This duration was shorter for patients in remission and still shorter for patients who had never developed PTSD. Similarly, a significant association was found between combat scale ratings and PTSD. The highest rating was observed in subjects who still had PTSD. The rating was lower in patients in remission and still lower in those who had never experienced PTSD. Having been wounded, which is one of the Laufer Combat Scale items and could be considered particularly traumatic, was strongly associated with PTSD. The findings are discussed in relation to the reliability and validity of the PTSD construct and to the contribution of factors other than stressor characteristics to PTSD symptom expression.