Cauda equina syndrome is a relatively uncommon condition typically associated with a large, space-occupying lesion within the canal of the lumbosacral spine. The syndrome is characterized by varying patterns of low back pain, sciatica, lower extremity sensorimotor loss, and bowel and bladder dysfunction. The pathophysiology remains unclear but may be related to damage to the nerve roots composing the cauda equina from direct mechanical compression and venous congestion or ischemia. Early diagnosis is often challenging because the initial signs and symptoms frequently are subtle. Classically, the full-blown syndrome includes urinary retention, saddle anesthesia of the perineum, bilateral lower extremity pain, numbness, and weakness. Decreased rectal tone may be a relatively late finding. Early signs and symptoms of a developing postoperative cauda equina syndrome are often attributed to common postoperative findings. Therefore, a high index of suspicion is necessary in the postoperative spine patient with back and/or leg pain refractory to analgesia, especially in the setting of urinary retention. Regardless of the setting, when cauda equina syndrome is diagnosed, the treatment is urgent surgical decompression of the spinal canal.