Cancer would appear to be the paradigmatic example of an acute or chronic illness that can precipitate posttraumatic stress disorder (PTSD). Few studies, however, have examined the applicability of PTSD criteria to patients with cancer. We examined the relationships between the experience of trauma, psychological distress, and PTSD among a waiting room sample of patients with breast cancer. We assessed 115 consecutive patients with breast cancer in the waiting room of a large comprehensive cancer center using measures of general distress, posttraumatic stress symptoms, and a semistructured diagnostic interview. A substantial minority (41%) reported responding to cancer with intense fear, helplessness, or horror (DSM-IV A2 criterion). However, cancer-related PTSD was uncommon (4%), and meeting the A2 criterion was a poor indicator of PTSD. Psychological distress was common (38%) and was strongly associated with A2, but was a poor predictor of PSTD. Although an intense negative emotional reaction to breast cancer was common, PTSD had low prevalence. Results suggest that using a trauma framework to understand the experience of most patients with cancer may be inaccurate.