Objectives: The aim of this specialist study is to give systematic overview of literature about possible benefits and risks from off-label use of quetiapine for treating posttraumatic stress disorder. While searching the literature and expert's opinions there is an ambition to find the role and efficacy of quetiapine in posttraumatic stress disorder. Materials and Methods: The development and creating of this paper was done in a systematic and retrospective review of literature in the field of posttraumatic stress disorder, pharmacotherapy for PTSD, second generation antipsychotics. Summary of Products Characteristic of Quetiapine, medical literature was used during the creation of this paper, and also search through database Pubmed for key words: posttraumatic stress disorder, antipsychotics, quetiapine and pharmacotherapy. At the end conclusions and my own thoughts were made about researched theme based on findings from clinical trials, expert's opinions and articles and based on specific features and nature of posttraumatic stress disorder. Conclusion: While treating the PTSD prescribed pharmacotherapy is chosen specifically to treat the main symptoms of disorder. In literature it can be found that one of the most disturbing symptoms are those that occur during the night, to be specific nightmares and insomnia. At the moment, double blinded, prospective, randomized clinical trials that had shown the efficacy of quetiapine for treating PTSD are not conducted but from smaller clinical trials and case reports the efficacy of this drug can be seen. Many researchers agree with the fact that for conducting normal life everyone should have good night rest and good quality of sleep. During the sleep body has an opportunity to rest from daily and accumulated stress and also from trauma. Patients with PTSD due to problems with insomnia and nightmares have less chance to rest during the sleep. This has a huge impact on patient's recovery. Furthermore, insomnia and nightmares are often called one of the most important symptoms to treat while prescribing drugs to patients with PTSD. During the literature research it was noted that quetiapine had shown the efficacy for treating the insomnia and had decreased the incidence of nightmares. The most data from literature indicate that quetiapine has better efficacy when it is prescribed in combination with other psychopharmacotherapy. For establishing the exact role and efficacy of quetiapine for treating PTSD additional double blinded, randomized, placebo-controlled or comparative clinical trials should be conducted.