OBJECTIVE: To determine sensory levels of injury using dermatomal somatosensory evoked potentials (SEPs) and compare with the neurological level of injury determined by ASIA standard in patients with thoracic spinal cord injury. METHOD: By stimulating segmental thoracic dermatomes, cortical SEPs were studied in nine spinal cord injured patients from T2 to T12 (9 men, mean age 41.8) and 20 normal adult men (mean age, 28.3). The SEP studies were performed bilaterally. RESULTS: In eight cases (44%) of the paraplegics tested, the neurological level of injury by dermatomal SEPs was same compared to the level of injury assessed by ASIA standard. In 15 cases (83%), there were no or one level difference of the level of injury between the levels by SEPs and ASIA standard. CONCLUSION: This study suggests that dermatomal SEP can be a useful tool in determination of the neurological level of injury in patients with thoracic spinal cord injury.