Complete surgical resection is a well-known therapeutic gold standard for spinal ependymoma, but it is associated with high postoperative morbidity. Intraoperative neuromonitoring (INM) is important for detecting and reducing the rate of surgical complications during this operative procedure. We report a case of postoperative paraplegia due to tumor bleeding during the operation. INM of the patient revealed abrupt loss of waveforms during the operation. This finding suggested that INM is helpful for detecting intraoperative hematomyelia and minimizing postoperative neurologic sequelae.