Although smaller hippocampi and amygdalae were found in cancer survivors with intrusions, associations between cancer-related posttraumatic stress disorder (PTSD) and these volumes are unknown. The authors performed MRI volumetric analyses of these regions in 15 cancer survivors with PTSD, 15 cancer survivors without PTSD, and 15 healthy comparison subjects. The authors also examined the correlation between PTSD symptom scores of the Impact of Event Scale and these volumes in the PTSD group. These volumes were not significantly different among the groups, but the intrusion score was inversely associated with the hippocampal volume. Results suggest intrusions, not PTSD diagnosis, might be associated with hippocampal volume.