Abstract: A previous investigation of this author revealed structural differences of the inferior prefrontal cortex (PFC) in children with symptoms of posttraumatic stress disorder (PTSD). In the present dissertation study, I investigated PFC structure in a new sample of children with and without PTSD symptoms. I compared gray matter volume in four sub-regions of the PFC between the two groups, and then explored whether volume was associated with PTSD symptom severity and cortisol levels in children with PTSD symptoms. PFC measurements were extracted from MRI data from a sample of 35 children (aged 10-16) with a history of trauma and symptoms of PTSD, who had undergone assessment for salivary cortisol levels, PTSD symptoms, and functional impairment. These measurements were compared to data from an age-equivalent control group consisting of 17 healthy children. Children with PTSD symptoms showed a significantly smaller volume of gray matter in the delineated ventral region of the PFC than control children. This finding ran counter to the author's hypothesis that previous findings of increased ventral PFC gray matter volume in children with PTSD symptoms would be replicated in this study. There was no relationship between regional PFC gray matter volume and ratings of PTSD symptoms or functional impairment. There was also no relationship between the decreased volume of the ventral PFC and cortisol levels in children with PTSD symptoms. The contrasts between these results and those observed in this author's previous study are discussed.