OBJECTIVE Postpartum hemorrhage (PPH) is one of the major preventable causes of maternal death in developing countries. Although the non-parenteral use of misoprostol is a big advantage especially in home births, its benefits in prevention of PPH is still debating. We aimed to assess the effect and side-effects of prophylactic oral, rectal or vaginal misoprostol on preventing postpartum hemorrhage comparing with no-treatment option. PATIENTS AND METHODS In a randomized clinical trial, during uncomplicated vaginal delivery, 248 women were assigned to receive one of the five treatment protocols in the third stage of labor which was managed routinely by early cord clamping and controlled cord traction. Maternal hemoglobin and hematocrit values, the duration of the third stage, and the incidence of blood transfusion was recorded. RESULTS There was no statistically significant differences between the antepartum and postpartum values of hemoglobin or hematocrit between the groups. The mean duration (11.8 ± 4.5 min) of the third stage of labor in oral+vaginal group was significantly shorter. Shivering was observed totally in 11 women and the differences were not significant between groups. CONCLUSIONS Despite misoprostol has benefit in treatment of postpartum hemorrhage, it has no remarkable effect in prophylaxis of atony-induced postpartum hemorrhage.