As mental health professionals practising in an evolving multidisciplinary trauma and recovery team in Omagh, Northern Ireland, the by now infamous Omagh bombing of 15 August 1998 brought abruptly to attention the potential for adverse psychological consequences resulting from exposure to such trauma. As nurse therapists, this event provoked interest in the entity of post-traumatic stress disorder (PTSD) as being one of the possible negative psychological consequences, and the relevance and application of cognitive theory and practice in its treatment. Whilst recognizing that there is no single cognitive theory or model of anxiety disorder, this paper focuses on the approach of Beck and allied approaches when referring to cognitive theory and practice. It is intended to proffer a broad overview of areas the authors consider relevant in order to develop an appreciation of the entity of PTSD, and its evolution, having given a synopsis of the event that provoked interest. Finally, acknowledgement and a brief explication of some of the theoretical models of PTSD to date will be made, and the relevance and application of cognitive theory and principals in the treatment of the disorder will be considered.