Introduction: Since duration of labor is an effective factor on outcome of pregnancy, the study was conducted to evaluate the effect of oral propranolol and oxytocin with oxytocin alone on duration of labor and type of delivery in nulliparous women with prolonged pregnancy. Methods: A double blind randomized controlled trial was performed on 146 nulliparous women with gestational age 40-42 weeks, cephalic presentation, bishop score ≥5, normal body mass index, intact of membrane, estimated fetal weight ≤4kg who referred to Khomeyni hospital of Ilam in 2009. Participants were classified into two groups, case group (propranolol and oxytocin) and control group (oxytocin alone).Before induction, the case group received 20 mg propranolol and control group received placebo with similar capsules orally TDS. Then induction was started initially with 2 mIU/min oxytocin in both groups and increased until obtain well contractions (3 contractions per 10 min) or 30 mIU/min. Data analyzes using SPSS software version 16, t-test and x2 test. p<0.05 was considered significant. Results: All participants were matched for factors affecting duration of labor. Mean± SD duration of active phase and second stages of labor in first and second days after induction was significantly shorter in case group than control group. Cesarean rate had significantly decreased in the control group but no significant difference of third stage and Apgar was found between both groups (p=0.987). Conclusion: Propranolol decreases the labor duration and the number of cesarean delivery
