The purpose of this study was to assess the effectiveness of two doses of intranasal midazolam on sedation of young children for dental treatment. Thirty uncooperative children, mean age of 32 months, who needed at least two restorative visits, participated in this study. The patients were assigned randomly to receive either 0.2 mg/kg or 0.3 mg/kg of midazolam intranasally, with the alternate regimen administered at the second appointment. All the children received 50% nitrous oxide, and were restrained in a Papoose Board (Olympic Medical Group, Seattle, WA) with a head holder. Degree of alertness, crying, and movement were evaluated at baseline and at 5-min intervals throughout the procedure. Evaluation of overall behavior at each session was performed by one investigator, blind to the dose, using a separate rating scale. The reliability of ratings was assessed by two investigators from videotapes of the procedures. Statistical analysis showed no differences (P > 0.05) in the behavior of the children receiving the two doses. Successful sedation, as assessed by lack of or minimal crying and/or movement that interrupted treatment, was observed in all the treatment visits with both doses (mean score 4.66 +/- 1.09 for 0.3 mg and 4.40 +/- 1.04 for 0.2 mg). No adverse effects were observed, and all the treatments were completed successfully.