English: In the course of duty, officers of the South African Police Services face highly stressful, life-threatening situations. This article discusses a model in which trait anxiety and years of service were specified as potential predictors of post-traumatic stress disorder. Structural equation modelling produced a satisfactory fit between the model and the observed data. In combination trait anxiety and years of service account for about 30% of the variance in symptoms of post-traumatic stress disorder. The article also makes recommendations as to how these results may usefully be applied in order to prevent the development of post-traumatic stress disorder among police officers.