BACKGROUND Bier block regional anesthesia was first described in 1908; however, it is uncommonly used for fears of cardiac and neurological complications. Although recent studies have documented safe usage in an adult population, no study to date has investigated its use in a pediatric setting. In addition, most emergency departments feel that splint placement is safer than casting after acute forearm fracture reduction in the pediatric population. However, to our knowledge there is no such study that documents the complication rates associated with immediate casting. The goal of this study was to assess the safety and efficacy of Bier block regional anesthesia and immediate cast application after closed reduction of pediatric forearm fractures. METHODS A retrospective review was conducted of patients treated for forearm fractures in a 2-year period at a major metropolitan pediatric hospital. Rates of complications and length and costs of the 2 procedures were analyzed. RESULTS A total of 600 patients were treated with Bier block regional anesthesia and 645 were treated with conscious sedation for displaced fractures of the forearm in the 2-year study period. No complications requiring admission were seen in either group. No patient experienced compartment syndrome or a need for readmission secondary to cast application. 2.2% and 4.3% (P=0.0382) of patients in the Bier block and sedation groups, respectively, needed their cast bivalved secondary to swelling. The average time from initiation of procedural sedation to discharge was 1 hour and 42 minutes, whereas the time to discharge from initiation of Bier block regional anesthesia was 47 minutes (P<0.0001). The average cost for a patient treated with procedural sedation was $6313, whereas the average cost for the Bier block regional anesthesia group was $4956. CONCLUSIONS Bier block regional anesthesia is a safe, efficient, and cost-effective method of reducing pediatric forearm fractures. Immediate cast application can be used without fear of major complications. METHODS Level III--retrospective review.