Four posttraumatic stress disorder (PTSD) scales were compared in a community sample of 330 American former prisoners of war and combat veterans of World War II. The Mississippi Scale for Combat-Related PTSD (M-PTSD), the Minnesota Multiphasic Personality Inventory-2 Pk PTSD scale, and the Impact of Event Scale (IES) all demonstrated moderate relationships with PTSD as defined by the Structured Clinical Interview for DSM-III-R. Comparative validities were similar to those observed in Vietnam veteran samples. Confirmatory factor analysis indicated that the 3 scales loaded significantly on 1 factor. The impact of Diagnostic and Statistical Manual of Mental Disorders (4th ed.) PTSD criteria changes was examined and found to be minimal. Implications for the use of the M-PTSD, Pk, and IES in combat-related PTSD assessment are discussed.