Erythropoietin (EPO) is a glycoprotein hormone that principally regulates erythropoiesis. EPO activity has been detected in various tissues including the female and male reproductive organs. It has been shown that EPO causes relaxation of smooth muscle in cardiovascular system. In the present study, it was aimed to investigate effects of EPO on spontaneous and oxytocin induced contractions of non-pregnant rat myometrium. Myometrial strips were prepared from virgin Wistar rats (weighing 200-250g) at oestrous stage. They were placed in an isolated organ bath chamber containing Krebs’ solution at 37 oC and pH 7.4, constantly bubbled with 95% oxygen + 5% carbon dioxide, and isometric contractions were recorded by using BIOPAC MP35 Data Acquisition System. Epoitin beta (rEPO) was added cumulatively at 0.1, 1 and 10 IU/ml concentrations to the tissue bath using myometrial samples showing regular spontaneous contractions for periods of 30 minutes. Effects of 1 IU/ml concentration of rEPO were also studied on oxytocin-induced myometrial contractions. This study was approved by the local ethics committee. rEPO inhibited both area under curve and frequency of spontaneous contractions at 1 and 10 IU/ml concentrations (ANOVA, n1, 2=9, f1=20.938, f2=20.492, p1,2=0.000). However, this inhibitory effect was not statistically significant at 0.1 IU/ml rEPO level (Tukey HSD, p1=0.051, p2=0.581). On the oxytocin stimulated myometrial samples, a single dose of 1 IU/ml rEPO was studied. The area under curve and frequency values of these samples were inhibited by rEPO (Student t test, n=9, t1=4.776, p1=0.000; t2=2.835, p2=0.012, respectively). In conclusion, our findings demonstrate that rEPO inhibited spontaneous and oxytocin induced rat myometrial contractions in vitro. The effect was dose dependent. Considering physiological levels of EPO, these results suggest that uterine contractility may be affected in women with chronic renal disease. Further studies are needed to elucidate the mechanism(s) of this inhibition as well as the possible effect of EPO on pregnant myometrium.