Objective\ To investigate the cardiovascular distribution of orphanin FQ (OFQ) and OFQ precursor mRNA in spontaneously hypertensive rat(SHR) and rabbit. Methods\ Reverse transcription polymerase chain reacrtion(RT PCR), and immunohistochemical method were used. Results\ The expression of OFQ precursor mRNA was detected from aorta, pulmonary artery, renal artery and vein of rat at a high level comparable with the amounts of brain, and a weak expression signal could also be observed in the atrium. The positive immunoreactive OFQ was detected in the tissues of aorta, atrium and renal of rabbit, as well as in smooth cells, endothelium and glomerulus. Conclusion\ These observations suggest that orphanin FQ might play a role in regulating the function of cardiovascular system and kidney, but the exact underlying mechanism needs further studying.