Magnetic resonance (MR) images of 16 peripheral nerve tumors (14 patients) were correlated with histopathologic appearance. Thirteen patients had surgically proved neuro-fibromatosis. There were 10 neurofibromas, four schwannomas, and two neurofibrosarcomas. Seven of the 10 neurofibromas showed a target pattern of increased peripheral signal intensity and decreased central signal intensity on T2-weighted images. This pattern appeared to correspond to a distinctive zonal histologic appearance that was found only in the neurofibromas. This pattern was not seen on MR images of the other peripheral tumors.