Background/aim: is study aims to investigate the relationship between emotion regulation characteristics and the e cacy of midazolam premedication. Materials and methods: Sixty-three children, aged 3 to 8 years old, with tonsillectomy and/or adenoidectomy and taking premedication with midazolam (Group 2) or without premedication (Group 1), were included in this study. e behavioral and emotional status of the children was evaluated with the Conners Parent Rating Scale-48 (CPRS-48) and Emotion Regulation Checklist (ERC). Age, sex, body weight, response to intravenous (IV) cannulation and mask, hemodynamic data, preoperative sedation scores [Wilton Sedation Scale (WSS)], postoperative pain intensity [Objective Pain Scale (OPS)], and emergence agitation (EA) level [Pediatric Anesthesia Emergence Delirium (PAED)] were recorded. Results: A total of 90.6% patients were quiet and sleepy in Group 2, and 25.8% in Group 1. e mean scores of OPS and PAED were higher in Group 1, and the percentage of patients with PAED score of >10 was 51.6% in Group 1 and 18.8% in Group 2 (P < 0.05). In Group 1, a signi cant correlation was found between PAED scores and WSS and the subfactors of the CPRS-48 (P < 0.05). A correlation was found between WSS and subfactors of ERS in Group 1 (P < 0.05). Conclusion: e incidence of anxiety and postoperative EA is increased in children with emotion regulation disorder, and midazolam premedication reduced the frequency of EA.