Over the last decade, EMDR(Eye Movement Desensitization and Reprocessing) has emerged as a promising new treatment for trauma and other anxiety-based disorders. However, neurobiological mechanism of EMDR has not been well understood. Authors report SPECT findings of two patients of PTSD before and after EMDR. Brain 99mTc-ECD-SPECT was performed before and after EMDR treatment. To evaluate the significance of changes in the regional cerebral perfusion, t-test was conducted on the resulting images using SPM99. In addition, clinical scales(CAPS, CGI, STAI) were employed to asses the changes in the clinical symptoms of the patients. After EMDR treatment, each showed significant improvement in clinical symptoms. The cerebral perfusion increased in bilateral dorsolateral prefrontal cortex, and decreased in the temporal association cortex. The differences in the cerebral perfusion between patients after treatment and normal controls decreased. These changes appeared mainly in the limbic area the and the prefrontal cortex. These results suggest that EMDR may show the therapeutic effect through 1) improvement in the emotional control by increased activity in the prefrontal cortex, 2) inhibited hyperstimuli on amygdala by deactivation of the association cortex, 3) inhibition on past trauma related memory, and 4) keeping the functional balance between the limbic area and the prefrontal cortex. This case report needs further replication from studies with larger sample.