Introduction: Induced abortion is defined as medical or surgical termination of pregnancy before fetal viability is achieved either due to maternal or fetal causes. Considering the potential complications of surgery and anesthesia, hospitalization, costs and time spent, medical induced abortion has replaced surgical treatment in the past two decades. The aim of this study was to evaluate the efficacy of vaginal MISOPROSTOl (Prostaglandin E1) in medical termination of first trimester pregnancy. Methods: This descriptive analytic study was done on 100 women in first trimester of pregnancy that referred for termination of their pregnancies to hospitals affiliated to Mashhad University of Medical Sciences in 2006. Vaginal MISOPROSTOl (800  mg) was prescribed and in cases of failure of induced abortion, a second dose followed 24 hours later. Control sonography was performed in all patients to detect any residue of pregnancy one week later. In failed cases of induced abortion or the presence of residue, dilatation and curettage (D & C) was done. Data were analyzed by Chi square test and p value of <0.05 was considered significant. Results: In our study 83 women (83%) had successful complete abortion. Medical abortion was achieved by first dose of vaginal MISOPROSTOl in 55 patients (62%) while in 28 enrolled women (34%) a second dose of vaginal MISOPROSTOl was needed. D & C was done in 17 cases. No side effects were noted due to vaginal MISOPROSTOl treatment in our study.Conclusion: Medical abortion in first trimester pregnancy with vaginal MISOPROSTOl showed a safe and cost-effective treatment modality.