The goal of this work was to analyze asymmetry of hippocampal formation in PTSD patients. The objects of the analysis were 10 MRI scans of patients with PTSD with established cognitive function damage. MRI scans were obtained using MAGNET IMPACT SIEMENS 1,0 TESLA in T1 and T2 relaxation. The measurement of hippocampal formation dimensions, and comparisons between the right and the left side were done using evaluate - distance program on the MRI instrument of the Institute of Radiology at Sarajevo Clinics Center. We tested 20 patients with PTSD 49,9 years of average age with standard deviation of 4,62 years. Based on the analysis of our results regarding the size of hippocampal formation in all the three projections (axial, coronal and sagital), in the group of patients with PTSD, we can the make the following observations: 1. In axial slice the length of hippocampal formation measured on the left and right side is significantly asymmetric in all patients. In the sagital slice, the hippocampal formation measured on the left side is in many cases longer than in the right - 50 %. In coronal slice no significant differences were found in the proportion of patients according to symmetry/asymmetry of hippocampal formation width on the left and right. 2. The difference in average size of hippocampal formation between the left and right side measured in axial and coronal slices is not statistically significant, but it is significant in sagitall slice. So, the results of this new research, showed smaller hippocampal dimensions in PTSD as measured using MRI. We have to be careful about what projection we are refusing to as being watched hippocampal formation because the results will depend on that. We suggest that future studies be done in more projections because of the importance of statistically significant conclusions. MRI - volumetric measurements have their value.