The delayed plantar reflex (DPR) is a pathologic flexor variant which requires unusually strong stimulation of the sole of the foot and is characterized by a prolonged interval between the stimulus and the response, slow and protracted plantarflexion of the great toe and/or other toes and slow return to the neutral position. The purpose of this study was to evaluate prospectively the functional outcome of spinal cord injury (SCI) patients based on the presence or absence of a DPR immediately following injury. Thirty-six subjects were evaluated within one week of injury. A complete neurological evaluation following American Spinal Injury Association (ASIA) standards was performed and the presence or absence of a DPR was noted on admission. Ambulation status and ASIA Impairment Scales were recorded at discharge from the rehabilitation unit and the data were analyzed by the Chi-square method with Yates' correction for continuity. The data demonstrated a high correlation of the DPR with motor complete injuries (p < 0.01) and a poor prognosis for recovery of ambulation (p < 0.01). Clinicians should recognize this abnormal reflex, which may be used in conjunction with a complete neurological examination, to help prognosticate future function in the acute SCI patient.