Depending on the approach to the upper brachial plexus, severe complications have been reported. We describe a novel posterolateral approach for brachial plexus block which, from an anatomical and theoretical point of view, seems to offer advantages. Twenty-seven patients were scheduled to undergo elective major surgery of the upper arm or shoulder using this new transscalene brachial plexus block. The success rate was 85.2% for surgery. Two patients required additional analgesia with IV sufentanil. In two others, regional anesthesia was inadequate. The side effects of this technique included reversible recurrent laryngeal nerve blockade in two patients and a reversible Horner syndrome in one patient. Further studies are needed to compare the transscalene brachial plexus block with other approaches to the brachial plexus.