Preschool age children often experience marked anxiety and physical pain during laceration repair. Locally infiltrated anesthetics or topical tetracaine, adrenaline, and cocaine (TAC) usually control the physical pain but have little or no effect on anxiety. Midazolam is a short-acting benzodiazepine with anxiolytic, hypnotic, and antegrade amnestic effects. In a double-blind, randomized clinical trial, we evaluated the efficacy of midazolam in alleviating anxiety during laceration repair in children less than 6 years old. On admission to the emergency department, anxiety level was determined on a scale of 1 to 4 based on a predetermined behavior criteria. Patients with high anxiety level (3 or 4) received a single oral dose of either midazolam (0.2 mg/kg) or placebo. The anxiolytic effect of midazolam was considered adequate if the anxiety level decreased two or more points (from 4 to less than or equal to 2 or from 3 to 1) during laceration repair. In the midazolam group (30), 70% of the children had a two-point or more decrease in anxiety level compared with 12% in the placebo group (25) (P less than .0001). No respiratory depression or other complications were noted in the midazolam group. We conclude that a single oral dose of midazolam (0.2 mg/kg) is a safe and effective treatment for alleviating anxiety in children less than 6 years old during laceration repair in the ED.