Exposure of rats to 3,3'-iminodipropionitrile (IDPN) results in neurofilament (NF)-filled swellings in the proximal axons of a number of large neurons, including sensory neurons in the dorsal root ganglia (DRG) and motor neurons in the spinal cord. The present report describes the effects of acute and chronic IDPN exposure on the vestibular ganglion (VG) neurons as compared to those on the DRG neurons. In the VG, IDPN induced intra-perikaryal accumulation of morphologically and immunocytochemically identified NFs. In the DRG of the same treated animals, IDPN induced proximal axonal swelling but no perikaryal NF accumulations. We concluded that the VG neurons preferentially express the IDPN-induced NF pathology in their myelinated cell bodies. It is hypothesized that the NF pathology occurring after IDPN is preferentially expressed in myelinated structures.