Objective: Hashimotos thyroiditis is the most common cause of goiter and acquired hypothyroidism in children and adolescents in non-iodine-deficient areas. In our study, it is aimed to determine the psychiatric disorders accom-panying Hashimotos thyroiditis which is a chronic disease in children and adolescents. Methods: In order to form the research group, 65 cases who were followed up and treated due to the diagnosis of Hashimotos thyroiditis in the Pediatric Endocrinology Department of the Trakya University Medicine Faculty were included in the study. In order to form the control group, 65 patients who were evaluated in the General Pediatrics Outpatient Clinic of the Pediatrics Department of Trakya University Medicine Faculty and did not have the chronic medical and neurodev-elopmental diseases were include in the study. In the child and adolescent psychiatry outpatient clinic, the Socio-demographic Data Form, the Strengths and Difficulties Questionnaire, Turgays Scale and the Schedule for Affective Disorders and Schizophrenia for School Age Children were applied to the cases in the research and control groups. Results: 38.4% of the cases with Hashimotos thyroiditis were diagnosed with at least one psychiatric disorder. In our study, the most frequent comorbid psychiatric disorder in children with Hashimotos thyroiditis was found as Specific phobia with rate of 20%. Specific phobia is followed by attention deficit hyperactivity disorder and depres-sive disorder with rate of 9.2%. In our study, there were no significant differences between patients with Hashimotos thyroiditis and healthy volunteers in terms of the attention deficit, hyperactivity, impulsivity, and oppositional defiant disorder. There was no significant difference between the cases with Hashimotos thyroiditis and the control group in terms of sensation, behavioral, attention deficit and mobility, peer relationships, social behavior and total difficul-ties scores. Discussion: When we evaluate the findings of our study, it can be considered that there was no any adverse effects of Hashimotos thyroiditis on the children's psychical status. However, due to being the limited num-ber of studies about this subject in the literature, it is necessary to support our findings with other studies conducted about this subject. [Anadolu Psikiyatri Derg 2019; 20(2.000): 189-195]