Objective: Oxytocin (OT) is involved in human reproduction and serves an important role in sexual arousal. Previous studies have documented that OT levels increase during sexual stimulation and arousal with a peak during orgasm in women. The purpose of this study was to investigate the effect of OT on vaginal tissue contractility in normal and castrated rats. Design and Method: Female Sprague-Dawley rats (230–240 g, n=30) were divided into three groups: control (n=10), bilateral ovariectomy (Ovx, n=10), and bilateral ovariectomy followed by subcutaneous injections of 17β-estradiol (Ovx+Est, 50 μg/kg/day, n=10). After 4 weeks, OT receptor level and distribution was assessed in rat vaginal tissue by Western blot analyses and immunohistochemistry. In organ baths, OT-induced changes in isometric tension were also assessed in isolated strips of vaginal tissue. Results: The OT receptor was well localized in subepithelial connective tissue and vaginal smooth muscle. Exogenous application of OT (10-9 - 10-5 M.) showed a dose dependent contractile effect. In the Ovx groups, the contractile effects of OT were significantly decreased compared to control and Ovx+Est groups (p<0.05). Conclusions: These data suggest that OT receptor may have a role in female sexual function. Further studies are needed to evaluate the role of oxytocin in female sexual arousal response.