Lumbar plexus block (LPB) is a suitable method for elder patients for lower extremity surgery. Many complications could be seen during LPB, but not as many as central block. In this case report, we aimed to report a total spinal block, an unusual complication. LPB with sciatic block was planned for a male patient, 76 years old, scheduled for total knee replacement due to gonarthrosis. The patient became unconscious after psoas compartment block with Chayen technique for LPB. The operation ended at 145th minute. The patient was admitted to intensive care unit until postoperative second day and discharged to home on fifth day of surgery. Main concern of patient monitorization should be an anesthesiologist. In this manner, we conclude that contacting to the patient should be ensured during these procedures. 2013 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.