The objective of this investigation was to assess the inter-examiner reliability of PTSD symptomatology by 12 clinical examiners who evaluated independently a single-case Vietnam-Era veteran, using videotaped clinician interviews with The Clinician Administered PTSD Scale-1 (CAPS-1). A second patient was utilized for cross-validation purposes. Data were analyzed using a specially designed Kappa statistic. In previous reliability assessments of the CAPS-1, a pair of examiners assessed multiple patients, and demonstrated evidence of high reliability and validity. As in previous reliability assessments, reliability was assessed both for frequency and intensity of PTSD symptomatology in both patients. Results indicated that the reliability levels of the CAPS-1 were consistently and almost exclusively in the excellent to perfect levels of inter-examiner agreement, as based upon both global assessments and on a symptom-by-symptom basis. The results of this investigation are interpreted in the broader framework of their applicability to assessing inter-examiner agreement in clinical trials or other large multi-site studies.