Cortical magnetic stimulation was performed in a consecutive series of 10 patients presenting within 15 days of traumatic spinal cord injury. In those patients with complete paraplegia or quadriplegia, motor evoked potentials at presentation were absent below the level of the lesion. Six months after the injury, potentials had returned in the biceps brachii and abductor pollicis brevis muscles in some quadriplegic cases, but remained absent from the tibialis anterior in all of this group. None of those with a complete lesion made a significant functional recovery. Of the three patients with incomplete quadriplegia, two showed a significant recovery after 6 months. Motor evoked potentials were recordable below the level of the lesion at presentation in these cases, although the latencies were prolonged. In the remaining patient who failed to improve, potentials were unrecordable throughout the study. This small pilot study suggests that cortical magnetic stimulation may be useful in refining the prognosis in patients with an incomplete spinal cord injury.