One hundred patients had major shoulder surgery with interscalene brachial and cervical plexus block anesthesia. Successful anesthesia was obtained by using this method in 82 patients. Failure was the result of incomplete anesthesia in 16 patients or the presence of a complication. Complications from high blood levels of anesthetic included loss of consciousness and respiratory depression in three patients and seizure in one. The block lasted a mean of eight hours, decreasing the need for postoperative analgesic medications. No postoperative medical complication developed. Ninety-one percent of the patients with successful blocks were satisfied with the procedure.