Twenty-two patients who underwent a surgical decompressive procedure for cervical spondylotic myelopathy were studied with magnetic resonance imaging to evalu ate the effectiveness of their decompressive procedures. Twelve patients were judged as adequately decom pressed by magnetic resonance imaging criteria. Ten patients exhibited evidence of residual cord indentation. This along with cord atrophy, gliosis, and abnormal spine curvature presumably contributed to, residual deficit in several patients. One patient underwent a second decom pressive procedure for residual cord indentation, which subsequently improved, as seen on his second postop erative magnetic resonance image. Magnetic resonance imaging was useful in distinguishing mechanical prob lems from intrinsic cord damage or atrophy. Magnetic resonance imaging should be used after operation in patients with residual deficit to detect patients who may be considered for a second decompressive procedure.