This study investigated the relationship between the level of combat exposure and army status (regular army soldiers vs national servicemen) and the subsequent development of combat-related post-traumatic stress disorder (PTSD). Sixty-four Australian infantrymen who were exposed to combat stress in Vietnam were used in this study. They were divided into four groups based on combat exposure and status as a regular or conscripted soldier. Subjects were assessed 23 years after their tour of duty in Vietnam for PTSD and psychiatric symptomatology using a PTSD inventory based on DSM-III-R criteria, the Self-report Checklist 90 (SCL-90), the Beck Depression Inventory (BDI), the Impact of Events Scale (IES), the Mississippi Scale for Combat-related PTSD (Mississippi Scale), the State and Trait Anxiety Inventory (STAI), and a demographic questionnaire. Results showed that 29.85% of the veterans have a positive diagnosis of PTSD according to self-report of symptoms based on the DSM-III-R criteria, while 54.89% of the remaining veterans suffer major symptoms of this disorder. MANOVA results show that neither the level of combat exposure nor the army status of the veterans had any significant effect on their psychiatric symptomatology as measured by the SCL-90, the BDI, the IES, and the STAI.