Intraoperative neurophysiology monitoring (IONM) is an essential tool in lumbar spine surgery for protecting neural structures and minimizing the risk of postoperative deficits. Techniques like electromyography (EMG) and motor evoked potentials (MEPs) provide real-time feedback on neural integrity, allowing surgeons to adapt their approach when changes occur. IONM has shown significant benefits in reducing complications, especially in complex or high-risk lumbar surgeries. This chapter highlights the role of IONM in enhancing patient safety and optimizing outcomes, underscoring its growing importance in lumbar spine procedures.