BACKGROUND The purpose of this study was to investigate patterns of mental disorders co-morbid with PTSD symptoms in young Israeli men exposed to combat. METHOD Six hundred and seventeen subjects were selected via a general population sample and evaluated in a two-phase case-identification procedure, culminating in a modified SADS-L interview, administered by psychiatrists. RESULTS Major depressive disorder (OR = 3.2), substance use disorders (OR = 1.9) and personality disorders (OR = 3.0) occurred more frequently in men reporting symptoms of PTSD than in men who had been under fire who did not report symptoms. With the possible exception of personality disorders, comorbid disorders did not constitute risk factors for PTSD. Comorbid PTSD and RDC disorders were associated with increased help-seeking. CONCLUSIONS The results suggest similar rates and types of PTSD comorbidity in Israeli war veterans as in veterans in the US assessed in general population studies, and are consistent with shared risk factors for PTSD and comorbid disorders.