The current study examines the effects of Posttraumatic Stress Disorder (PTSD) and menstrual cycle phase on psychophysiologic reactivity to a loud tones task in a population of female trauma survivors. Estradiol and progesterone fluctuate throughout the menstrual cycle; prior research has shown the variety of effects these hormones have on the Hypothalamic-Pituitary Adrenal (HPA) axis, glucocorticoids, stress and anxiety homeostasis, and conditionability. We hypothesized greater reactivity for participants with PTSD, and that menstrual cycle would moderate the effects of PTSD and performance on the loud tones task. Results indicated heart rate was higher in participants in the mid-luteal phase than early follicular phase. Several results were surprising, including that participants with PTSD demonstrated less startle reactivity and faster habituation (as measured using the left orbicularis electromyogram (O-EMG) measure) than participants in the trauma control group for. Considerations are made for demographics, sample size, and the number of potential underlying mechanisms for PTSD.