Posttraumatic stress disorder (PTSD) is associated with larger heart rate (HR), skin conductance (SC), and eyeblink responses to sudden, loud tones. The present study tested this association in female nurse veterans with PTSD related to witnessing patients' death, severe injury and/or suffering during their Vietnam service. Nurses with current, past but not current, or who never had PTSD listened to 15 consecutive 95-dB, 500-ms, 1000-Hz tones with sudden onsets, while HR, SC, and eyeblink responses were measured. Nurses with current PTSD produced significantly larger averaged HR, but not SC or eyeblink responses across tone trials. A larger HR response to loud tones is one of the most robust physiologic findings in PTSD and may reflect increased defensive responding.