The relation between improvement of myelopathy achieved by surgery and postoperative spinal cord morphologic changes was investigated by magnetic resonance imaging in 51 patients with cervical myelopathy. In 22 patients, the cord indentation disappeared completely (Type I), in 23 it partially disappeared (Type II), and in 3 it remained unchanged (Type III). In three patients the cord enlarged after surgery (Type IV). With the exception of Type IV, increased restoration of cord morphology paralleled improvement in the myelopathy, suggesting that morphologic changes closely reflect neurologic recovery. In Type IV, notwithstanding the peculiar postoperative reaction, improvement was relatively good, and shrinkage of the cord enlargement was seen after 1 year. This kind of postoperative change has not been demonstrated previously by other conventional imaging methods.