The ability to regulate emotions is essential for human well-being. Among posttraumatic stress disorder (PTSD) patients, the capability to control emotions is impaired. Trauma-focused cognitive behavioral therapy is a recommended treatment for patients diagnosed with PTSD. Usually, cognitive reappraisal is considered the primary regulation technique in cognitive behavioral therapy treatment. The strategy aims to decrease negative or increase positive emotions by changing the interpretation of an event to alter the meaning of the situation. The aim of this thesis was to conduct a systematic review of the neural correlates of cognitive reappraisal among post-traumatic stress disorder patients. Through a systematic search, screening, and selection process out of initial 545 articles, six studies were included for data extraction and discussion. Using functional magnetic resonance imaging, participants utilized the strategy of cognitive reappraisal during an emotion regulation task in the scanner. Using functional magnetic resonance imaging, the neural activity of the participants in the included studies was compared during a cognitive reappraisal task. The result revealed a tendency of decreased activity in prefrontal cortices in PTSD patients during reappraisal compared to controls, indicating deficient recruitment of prefrontal cortices in PTSD patients during reappraisal.