This paper summarizes strengths and weaknesses of clinical utility of tests that diagnose Vietnam combat-related Post-Traumatic Stress Disorder (PTSD). Weaknesses reviewed are: excessive reliance upon one kind of measure of Index Diagnosis; failure to control for varying prevalence rates across samples; failure to compare accuracy across response modalities. Strengths that emerge from the review are that self-report measures have proven to be highly sensitive, and psychophysiological measures have been demonstrated as highly specific. Whereas one single "gold standard" measure of PTSD has yet to be devised, clinical researchers can continue to have confidence in the use of multiple measures.