Eighteen adult patients presenting with acute transverse myelitis (ATM) were evaluated using magnetic resonance imaging. Only 7 had abnormal scans showing an area of increased signal intensity within the cord solely on T2 weighted images; Tl weighted images were normal. The MRI abnormality did not correlate with the cause of the transverse myelitis, the extent of maximum neurological deficit, or the prognosis. A scan performed more than 5 days after the onset of disease was most likely to be positive. Even though the prognostic value of MRI in ATM may be limited, it remains a valuable technique for ruling out other causes of noncompressive spinal cord lesions, such as hemmorhage, vascular malformation, or tumor.