Expression of nerve growth factor receptor (NGFR) was found in the mouse olfactory epithelium after olfactory nerve transection, although no immunoreactivity to NGFR was detectable in the olfactory epithelium in the control animals. After axotomy, however, NGFR-immunoreactive cells transiently appeared in the supporting cells, receptor neurons and basal cells between postoperative day 7 and 35, and thereafter disappeared by postoperative day 49. The results indicate that nerve growth factor may contribute to the regeneration of olfactory receptor neurons after olfactory nerve transection.