Background: The purpose was to investigate if potentially stressful reminders of the intensive care unit (ICU) stay influenced variability in transient skin conductance responses, and whether such changes were associated with post-traumatic stress symptoms (PTSS), and development of symptoms over time. Methods: Thirty patients with an ICU length of stay > 48 h were included in the study. Within the week after ICU discharge (T1), patients were exposed to authentic ICU sound and questions regarding traumatic ICU memories while skin conductance reactivity was monitored. PTSS was assessed using PTSS-10 at T1 and again 3 months later (T2). Changes in number of skin conductance fluctuations per second (NSCF) between baseline and during the cueing conditions and in relation to PTSS scores (T1) were investigated. PTSS scores at T2 and changes between T1 and T2 (PTSS-CS) were used to investigate if reactivity in NSCF could predict symptoms of PTSD. Results: The results showed increases in NSCF during both situational and verbal cueing, compared to baseline. However, no relation to PTSS scores was indicated. Negative correlations between NSCF during situational cueing and both PTSS-T2 and PTSS-CS were found among women, but not among men. Conclusion: A low variability, or reactivity in skin conductance responses to situational cues could imply a risk of developing, or not being able to recover from, symptoms of PTSD in women. As such, the measurement could be used to predict this risk in women. However, further studies are necessary to evaluate this area of application.