The opioid growth factor receptor (OGFr) interacts with a specific opioid growth factor ligand (OGF), chemically termed [Met5]-enkephalin, to maintain homeostasis in a wide variety of normal and abnormal cells and tissues. The mechanism underlying the function of OGFr requires that the receptor translocates to the nucleus. However, the mechanism of nuclear export of OGFr is unknown. Studies utilizing both endogenous OGFr, and exogenously expressed OGFr-eGFP, demonstrated that OGFr is exported from the nucleus in a CRM1 dependent manner.