Midazolam is a recently introduced benzodiazepine with a half life of 1-4 hours. Midazolam (0.15 mg/kg) has been compared with diazepam (0.2 mg/kg) for sedation during locoregional anesthesia in 60 premedicated patients. No difference among the two groups for heart rate, bloodpressure, respiratory rate and incidence, and duration of apnoea was noticed after an i.v. bolus administration. The recovery time was equal in both groups. Midazolam was significantly less painful at injection. The sedation pattern between both groups is only different at 60 minutes, where more better sedated patients are seen in the midazolam group. Except the pain at injection and a better sedation pattern after 60 min. the differences in the other parameters are only borderline.