Peripheral compression neuropathy is a common clinical entity but little human nerve material has been available for study. It has been difficult to develop an experimental model of chronic nerve compression which is reliable and reproducible, making it difficult to assess the various treatment modalities currently in use to manage this problem. In a recent study using a rat model, connective tissue and nerve fiber changes associated with chronic nerve compression were described by the authors. The present study expands this same model of chronic nerve compression to the multifascicular median nerve of the cynomolgus monkey, using this model to test whether or not current surgical treatment modalities for nerve entrapment will alter the course of chronic nerve compression. Using histologic and morphometric parameters, there did not appear to be a difference between nerves treated by decompression alone or by decompression and internal neurolysis. Total number of nerve fibers remained constant, as did axon size, but a demyelinating process was demonstrated which is a significant component of chronic nerve compression. Although the small number of experimental animals makes precise evaluation of the clinical modalities impossible, the authors expect that further study of the multifascicular median nerve of the cynomolgus monkey will prove to be a useful source of future experimental evidence and will help to interpret the diverse therapeutic and operative techniques currently in use.