Bariatric surgery operations in Turkey increasingly expands as well as in the world. Growing literature supports that psychiatric and psychosocial assessment of obesity surgery patients are crucial. Many of the weight loss surgery centers applies multidisciplinary approach including psychiatric and psychological assessments. However, a worldwide accepted guideline to manage obesity surgery patients regarding psychiatric and psychosocial assessment, is not available. Instead, there are variety of expert consensus texts are used by different centers which taken into account by the health authorities. Unfortunately, neither expert consensus texts nor a guideline are available yet, in Turkey. Patients, bariatric surgeons and even mental health professionals have been underestimated the importance of psychiatric evaluation in bariatric surgery in Turkey. The main themes to be discussed in this context are the necessity of psychiatric evaluation, assessment methods, qualification and competency of the professionals and the quality of the assessments. Patients should be screened routinely in terms of the presence of eating disorders, mood disorders, substance use disorders and other psychiatric disorders in both pre- and surgical period and those who needed should be follow for further psychiatric evaluation and treatment. Careful psychiatric and psychosocial assessment of the patients is important with regard to the improvement of the quality of life as well as preventing adverse effects on weight loss in the post-operative period. This article is aimed to review the current literature and guidelines in order to explore the main issues in psychiatric aspects of the assessment of bariatric surgery patients. It is also aimed that this article provide an orientation for the guidelines will be prepared in Turkey. This article has focused on the assessment of the common psychiatric conditions before and after bariatric surgery. Effectiveness of the treatments, selection of the interventions and advantages/disadvantages of psychopharmacologic, psychotherapeutic or psychosocial interventions are excluded from the scope of this article. It is obvious that to discuss these issues in the relevant platforms and to develop a guideline, are needed in order to reach a common approach. [Anadolu Psikiyatri Derg 2016; 17(0.200): 5-45]