BACKGROUND We conducted a prospective, randomized, double-blind, placebo-controlled study to verify the hypothesis that intranasal dexmedetomidine premedication can reduce the minimum alveolar concentration of sevoflurane for laryngeal mask airway insertion in children. METHODS Ninety American Society of Anesthesiologists (ASA) physical status I subjects, aged 3-7 years, were randomized to three equal groups to receive saline (Group S), dexmedetomidine 1 μg · kg(-1) (Group D1 ), or dexmedetomidine 2 μg · kg(-1) (Group D2 ) approximately 45 min before anesthesia. The minimum alveolar concentration for laryngeal mask airway insertion of sevoflurane was determined according to the Dixon's up-and-down method. Emergence delirium was evaluated using the Pediatric Anesthesia Emergence Delirium (PAED) scale in the postanesthesia care unit (PACU). RESULTS Dexmedetomidine premedication of 1 and 2 μg · kg(-1) was associated with reduction in sevoflurane from 1.92% to 1.53% and 1.23%, corresponding to decrease of 20% and 36%, respectively. The peak PAED scores (median [IQR]) were 9 [8-11.5], 5 [3-5.3], and 3 [2-4] in Group S, Group D1, and Group D2 , respectively. The incidence of emergence delirium (defined as peak PAED score ≥ 10) was significantly lower in Groups D1 and D2 than in Group S (P < 0.001). Simultaneously, the induction qualities and the parent's satisfaction scores were significantly higher in Groups D1 and D2 than in Group S (P < 0.001). CONCLUSIONS Intranasal dexmedetomidine premedication produces a dose-dependent decrease in the minimum alveolar concentration for laryngeal mask airway insertion of sevoflurane and emergence delirium in the PACU.